Polymers derived from ethylene and 1-butene for use in the preparation of lubricant disperant additives

ABSTRACT

The invention pertains to oil soluble copolymers derived from ethylene and 1-butene which have a number average molecular weight between about 1,500 and 7,500, at least about 30 percent of all polymer chains terminated with ethylvinylidene groups, and ethylene-derived content of not greater than about 50 weight percent, and which form solutions in mineral oil free of polymer aggregates, as determined by light scattering measurements. Lubricating oil additives, particularly dispersants, produced by the functionalization and derivatization of these copolymers have enhanced performance (e.g., improved dispersancy and pour point) in lubricating oil compositions, attributable in part to the combination of properties characterizing the copolymers.

This is a divisional of application Ser. No. 08/610,782, filed Mar. 11,1996, now U.S. Pat. No. 5,663,130; which is a divisional of applicationSer. No. 08/445,574, filed May 22, 1995, now U.S. Pat. No. 5,498,809;which is a continuation of application Ser. No. 07/992,192, nowabandoned.

FIELD OF THE INVENTION

The invention relates to polymers derived from ethylene and 1-butenewhich possess a certain combination of chemical and physical propertiesrendering the polymers particularly suitable as "polymer backbones" forthe preparation of lubricating oil additives, particularly dispersants.The invention also relates to improved oil-soluble dispersant additivesprepared from the polymers and useful in lubricating oil compositions,and to concentrates containing the oil-soluble dispersant additives.

BACKGROUND OF THE INVENTION

Hydrocarbon oil compositions typically comprise a mixture of at leastone hydrocarbon base oil and one or more additives, where each additiveis employed for the purpose of improving the performance and propertiesof the base oil in its intended application; e.g., as a lubricating oil,heating oil, diesel oil, middle distillate fuel oil, and so forth.Lubricating oil compositions face rather stringent viscosityrequirements, as set, for example, by ASTM specifications. Suchcompositions must meet a minmum viscosity requirement at hightemperature (i.e., at least about 100° C.) and a maximum viscosityrequirement at low temperature (about -5 to -30° C.). The minimumviscosity requirement at high temperature is intended to prevent the oilfrom thinning during engine operation to the point at which excessiveengine wear and increased oil consumption would result. The maximumviscosity requirement at low temperature facilitates engine start-up incold weather and also ensures the cold oil has sufficient pumpabilityand flowability to avoid engine damage due to insufficient lubrication.

In formulating a lubricating oil composition which meets both the lowand the high temperature viscosity requirements, a formulator can use asingle lubricating base oil of desired viscosity or a blend of oils ofdifferent viscosities, and he can manipulate the kinds and amounts ofadditives that must be present to achieve not only the viscosityrequirements, but also requirements specified for other properties, suchas dispersancy, pour point and cloud point. Generally, the mere blendingof oils having different viscosity characteristics does not enable theformulator to meet the low and high temperature viscosity requirementsof lubricating oil compositions. Instead, the primary tool for meetingthe requirements is the use of viscosity index improving additives,hereinafter referred to as viscosity index improvers or, more simply, VIimprovers.

A VI improver is conventionally an oil-soluble long chain polymer, oftena hydrocarbon-based polymer with a number average molecular weight inthe range of 20,000 to 200,000. The large size of these polymers enablesthem to significantly increase kinematic viscosities of base oils evenat low concentrations. Unfortunately, lubricating oil solutionscontaining these VI improvers are non-Newtonian in nature. As a result,these solutions tend to give lower viscosities than expected in a highshear environment, such as that found in an operating internalcombustion engine. It is believed that this behavior arises fromshear-induced alignment of the VI polymer chains. Consequently, the VIimprovers increase the low temperature viscosity of a lubricating baseoil to a greater extent than they increase its high temperatureviscosity. As a result, the two viscosity requirements for a lubricatingoil composition become increasingly antagonistic as increasingly higherlevels of VI improver are employed. Eventually, a point can be reachedwhere the amount of VI improver added to achieve the required minimumviscosity at high temperature precludes the possibility of meeting therequired maximum viscosity at low temperature. Accordingly, constraintsexist on the amount of VI improver which a formulator can employ for agiven lubricating base oil or base oil blend to meet the low and hightemperature viscosity requirements for the lubricating oil composition.

The task of formulating a lubricating oil composition is morecomplicated than merely selecting the appropriate kind and amount of VIimprover to add to the base oil. In addition to VI improvers,lubricating oil compositions typically contain dispersant additives,which can also affect the viscosity characteristics of the composition.Dispersants are typically polymeric materials with an oleophiliccomponent providing oil solubility and a polar component providingdispersancy. Dispersants generally have a number average molecularweight of about 10,000 or less, and, consequently, have polymer chainsmuch smaller than those of a typical VI improver. Among the materialswhich have been employed as dispersants are hydrocarbon polymersmodified to contain nitrogen- and ester-based groups. Polyisobutylene isperhaps the hydrocarbon polymer most commonly used in the preparation ofdispersants, although other hydrocarbon polymers, such asethylene-α-olefin copolymers, can be employed as well. The primaryfunction of a dispersant is to maintain in a suspension in the oil anyinsolubles formed by oxidation, etc. during use, thereby preventingsludge flocculation and precipitation. The amount of dispersant employedis dictated and controlled by the effectiveness of the particularmaterial in achieving its dispersant function. Motor oils commerciallyavailable at U.S. service stations typically contain about four times asmuch dispersant as VI improver, based on active ingredient.

Conventional dispersants can also increase the low and high temperatureviscosity characteristics of a base oil by virtue of their polymericnature. However, because dispersant polymer molecules are much smallerthan those of a VI improver, the dispersant is much less shearsensitive. As a result, a dispersant contributes more to the lowtemperature viscosity of the lubricating oil relative to itscontribution to the high temperature viscosity than does a VI improver.Moreover, the dispersant, with its shorter polymer chains, contributesmuch less to the high temperature viscosity of the base oil in anabsolute sense than does the VI improver. Thus, the magnitude of the lowtemperature viscosity increase induced by the dispersant can exceed thelow temperature viscosity increase induced by the VI improver withoutthe benefit of a proportionately greater increase in high temperatureviscosity as obtained from a VI improver. Consequently, as thedispersant-induced low temperature viscosity increase causes the lowtemperature viscosity of the oil to approach the maximum viscositypermitted at low temperature, it becomes increasingly difficult tointroduce an amount of VI improver sufficient to meet the minimumviscosity required at high temperature without crossing the lowtemperature viscosity threshold.

A lubricating oil composition formulated with a kind and amount ofdispersant and VI improver sufficient to meet the low and hightemperature viscosity requirements and still achieve effectivedispersancy does not necessarily end the formulator's task. Thelubricating oil composition must meet other performance criteria, suchas pour point and cloud point, which may necessitate the employment ofstill other additives.

Cloud point (ASTM D2500) is the temperature at which wax crystals firstappear as a haze in a hydrocarbon oil upon cooling. These wax crystalstypically have the highest molecular weight of the waxes in thehydrocarbon oil and, therefore, the lowest solubility. The cloud pointof a hydrocarbon oil reflects the temperature at which problems infiltering the oil are encountered. However, the cloud point of alubricating oil (as against a fuel oil) is of less significance than isits pour point, because the filters typically encountered by alubricating oil (e.g., oil filters for internal combustion engines) havea relatively large pore size, and filter plugging is less of a problem.

Pour point is the lowest temperature at which a hydrocarbon oil willpour or flow when chilled without being disturbed under specifiedconditions. As the hydrocarbon oil is chilled, wax in the oilprecipitates into crystals which form a network. The pour point of theoil is marked by the temperature at which the fluid component of the oilis immobilized by the wax crystal network. See, e.g., Mark, Herman,editor, Encyclopedia of Polymer Science and Engineering, vol. 11, JohnWiley & Sons, New York, 1988, pg. 26-27. The lubrication of an engine orother equipment at temperatures near and below the pour point issignificantly impaired, because the distribution of the chilled oil bypumping or siphoning is difficult or impossible. Operation of the engineor other equipment under such conditions will quickly result insignificant damage and ultimately failure.

Because the waxes contributing to low-temperature problems are presentin essentially all non-synthetic hydrocarbon oils used today, variousadditives have been developed to beneficially influence the oils' lowtemperature flow properties. These additives are generically referred toas lubricating oil flow improvers (LOFI's) or pour point depressants.The LOFI's act to modify the size, number, and growth of wax crystals inchilled lubricating oils in a manner imparting improved handling,pumpability, and/or vehicle operability at low temperatures.

The majority of LOFI's are or contain polymers of one of two generaltypes--backbone polymers and side-chain polymers. The backbone polymers,such as ethylene-vinyl acetate (EVA) copolymers, have various lengths ofmethylene segments randomly distributed in the backbone of the polymer,which associate or cocrystallize with the wax crystals. Extended waxcrystal growth, and the concomitant formation of crystalline waxnetworks, is inhibited, however, by the branches and non-crystallizablesegments in the polymer.

The side-chain polymers, the predominant variety of LOFI's, havemethylene segments in their side chains, which are preferablynon-branched side chains. These polymers work similarly to the backbonepolymers except the side chains have been found to be more effective ininhibiting extended wax crystal growth in isoparaffins as well as thenormal paraffins found in lube oils. More specifically, LOFI's aretypically derived from unsaturated carboxylic acids or anhydrides whichare esterified to provide pendent ester groups derived from a mixture ofalcohols. Representative examples of this type of side chain LOFIinclude dialkyl fumarate-vinyl acetate copolymers and esterifiedstyrene/maleic anhydride copolymers.

Unfortunately for the formulator, the LOFI's and other additives addedto control the pour point, etc. of the lubricating oil composition mayinteract with the VI improver and the dispersant in a manner adverselyaffecting the composition's viscosity and dispersancy. Conversely, thedispersant and/or VI improver may contribute adversely to theperformance of these other additives. Furthermore, even in the absenceof other additives, the dispersant and VI improver may interact with thebase oil itself to degrade the cloud point, pour point, etc the oilwould otherwise have.

As an example, dispersants employing ethylene-α-olefin copolymers,unlike those based upon polyisobutylene, possess linear methylenesegments derived from sequential units of ethylene in the polymer chain.These methylene segments possess the capability of interacting with thewaxes present in the lubricating base oil. In some cases theseinteractions can be harmful to the low temperature properties of the oiland can in certain circumstances counteract and defeat the effect soughtto be induced by the LOFI. Thus, dispersants based uponethylene-α-olefin copolymer backbones must be carefully selected toavoid adverse wax interactions, while simultaneously achieving theproper overall high and low temperature viscosity requirements of theoil, which may or may not be significantly affected by the waxinteraction. Furthermore, these problems must be solved in such a waythat the dispersancy of the ethylene-α-olefin-based dispersant remainsacceptable.

As already noted, short-chain hydrocarbon polymers modified to containcertain polar groups, particularly nitrogen- and ester-based groups,have been widely used as ashless dispersant additives in lubricatingoils. The nitrogen- and ester-based dispersants can be prepared by firstfunctionalizing the long-chain hydrocarbon polymer with maleic anhydrideto form the corresponding polymer substituted with succinic anhydridegroups, and then derivatizing the succinic anhydride-substituted polymerwith an amine or an alcohol or the like. Polyisobutylene has often beenthe polymer of choice, chiefly because it is readily available bycationic polymerization from butene streams (e.g., using AlCl₃catalyst). Such polyisobutylenes generally contain residual unsaturationin amounts of about one ethylenic double bond per polymer chain,positioned along the chain. The ethylenic double bonds serve as sitesfor functionalizing the polyisobutylenes by, for example, the thermal"ene" reaction (i.e., by direct reaction with maleic anhydride or one ormore other dicarboxylic acid moieties).

The polyisobutylene polymers (PIB) employed in most conventionaldispersants are based on a hydrocarbon chain of a number averagemolecular weight (M_(n)) of from about 900 to 2500. PIB having a M_(n)of less than about 300 gives rather poor performance results whenemployed in dispersants because the molecular weight is insufficient tokeep the dispersant molecule fully solubilized in lubricating oils. Onthe other hand, high molecular weight PIB (M_(n) >3000) becomes soviscous that conventional industrial practices are incapable of handlingthis product in many operations. This problem becomes much more severeas the PIB molecular weight increases to 5,000 or 10,000.

Increased amounts of terminal ethylenic unsaturation in polyisobutylene(so-called "reactive polyisobutylene") have been achieved by BF₃-catalyzed polymerization of isobutylene. Exemplary of referencesdisclosing these polymers is U.S. Pat. No. 4,152,499. Nonetheless, thereactive polyisobutylenes can still contain substantial amounts ofunsaturation elsewhere along the chain. Furthermore, it is difficult toproduce reactive polyisobutylene polymers at molecular weights ofgreater than about 2,000, and, in any event, the reactivepolyisobutylenes still have the above-noted viscosity increasedisadvantages as their molecular weights are increased.

A variety of hydrocarbon polymers have been disclosed to be suitablepolymer backbones for the preparation of ashless nitrogen and esterdispersants. U.S. Pat. No. 4,234,435, for example, discloses dispersantsprepared from polyalkenes with a Mn value of from 1,300 to about 5,000and M_(w) /M_(n) of about 1.5 to about 4. The polyalkenes arehomopolymers or interpolymers of polymerizable olefin monomers, usuallypolymerizable terminal olefin monomers, of 2 to about 16 carbon atoms.The polyalkenes are functionalized by reaction with one or more acidicreactants such as maleic acid, fumaric acid and maleic anhydride. Thispatent, however, provides no examples directed to the preparation ofsuitable polyalkene ethylene-α-olefin interpolymers or their use asdispersant backbones.

It is generally known that ethylene-α-olefin copolymers can be preparedby polymerizing ethylene and the α-olefin co-monomer using conventionalZiegler-Natta catalysts (e.g., VCl₄ or VOCl₃ with a halide source, suchas organoaluminum halides and/or hydrogen halides). However, because ofthe relatively high activity of these catalysts, the resultingcopolymers tend to have number average molecular weights well in excessof about 10,000 and thus are generally not suitable for use as polymerbackbones for dispersants. For example, ethylene-propylene (EP) polymersand ethylene-propylene-diene terpolymers (EPDM) having a viscosityaverage molecular weight (M_(v)) of from about 20,000 to 300,000 areproduced using Ziegler catalysts. These high molecular weight EP andEPDM polymers find use as viscosity index improvers. See, e.g., U.S.Pat. Nos. 3,563,964; 3,697,429; 4,306,041; 4,540,753; 4,575,574; and4,666,619. Other high molecular weight olefin polymers produced usingZiegler catalysts, such as polypropylenes and ethylene-1-butenecopolymers, have also been disclosed to be useful as viscosity indeximprovers. See, e.g., U.S. Pat. No. 4,540,756.

It is also known in the art that ethylene-α-olefin copolymers useful asviscosity index improvers may, when functionalized with acid moietiessuch as maleic anhydride and subsequently reacted with an amine, beemployed as multifunctional viscosity index improvers. See, e.g., U.S.Pat. Nos. 3,316,177; 3,326,804; 4,160,739; 4,161,452; 4,171,273; and4,517,104.

Certain of the references disclosing the production of ethylene-α-olefincopolymers using conventional Ziegler catalysts include within theirscope the production of copolymers having relatively low molecularweights; i.e., values of M_(n) below about 10,000. However, thesereferences often disclose the lower molecular weight copolymers to beoutside the preferred ranges, and they often do not provide examples ofthe preparation or use of low molecular weight polymers. U.S. Pat. No.4,863,623, for example, discloses lubricant additives havingviscosity-improving, dispersancy and anti-oxidant properties, preparedfrom ethylene copolymers and terpolymers of C₃ to C₁₀ α-monoolefins andoptionally non-conjugated dienes or trienes. To prepare the additive,the copolymer or terpolymer is first grafted with an ethylenicallyunsaturated carboxylic function, preferably maleic anhydride or aderivative thereof, by the thermal "ene" process or by grafting insolution or in solid form using a radical initiator, and the graftedmaterial is then further derivatized with an amino-aromatic polyaminecompound. The ethylene copolymers and terpolymers are disclosed to havea molecular weight ranging from about 5,000 to 500,000 and an α-olefincontent of 20 to 85 mole %. The patent discloses the copolymers andterpolymers can be prepared using Ziegler type catalysts. The preferredmolecular weight range is disclosed to be 25,000 to 250,000, and theexamples are directed to the use of EP copolymers having an averagemolecular weight of 80,000.

Along similar lines is Canadian Patent Application 2,021,959. Theapplication discloses dispersant and anti-oxidant lubricant additivesprepared from ethylene copolymers and terpolymers of C₃ to C₁₀α-monoolefins and optionally non-conjugated dienes or trienes. As inU.S. Pat. No. 4,863,623 supra, the additive is produced by firstthermally or radically grafting the copolymer or terpolymer with anethylenically unsaturated carboxylic acid material and then reacting thegrafted polymer with an amino-aromatic polyamine compound. The ethylenecopolymers and terpolymers are disclosed to have a molecular weightranging from about 1,000 to 40,000. It is further disclosed that thecopolymers and terpolymers can be prepared using Ziegler catalysts. Butit is also noted that many polymerization processes produce thecopolymers and terpolymers with molecular weights substantially above75,000 thus requiring that the polymers be degraded, usuallymechanically or thermally, to obtain polymers in the prescribed M_(n)range of 1,000 to 40,000. The examples are directed to the grafting ofEP copolymers having number average molecular weights higher than10,000.

Ethylene-α-olefin copolymers which have sufficiently low molecularweights to be useful dispersant polymer backbones can be prepared usingconventional Ziegler-Natta catalysts by conducting the polymerization inthe presence of a molecular weight regulator such as hydrogen. A keydisadvantage to the use of hydrogen as a chain stopper is that it canresult in the saturation of the olefinic double bond content in thecopolymers. The resulting low unsaturation content of the copolymersmakes their functionalization by a thermal "ene" reaction highlyunattractive.

U.K. Patent 1,329,334 exemplifies the use of a conventionalZiegler-Natta catalyst for the preparation of ethylene-α-olefincopolymers of relatively low molecular weight. The patent discloses theproduction of ethylene polymer wax by polymerizing ethylene andoptionally an α-olefin in the presence of hydrogen using a catalystcomposed of a titanium or vanadium halogen compound supported on acarrier (a hydrocarbon-insoluble Mg compound) and an organo-aluminumcompound. The molecular weight and density of the polymer wax arecontrolled by the amount of hydrogen and/or α-olefin used in thepolymerization. At the temperatures and pressures used in thepolymerization, the content of double bonds in the polymer wax isreduced. The polymer wax is disclosed to have a M_(v) in the range of400 to 20,000. The wax may be oxidized without the formation ofcross-linkages due to the small content of double bonds in the wax, andthe oxidized wax may be modified by reaction with a maleic acidcompound. The patent contains an example disclosing the production of anethylene-1-butene polymer wax containing 28 ethyl groups per 1000 carbonatoms, which is equivalent to about 94 mole % ethylene assuming theethyl groups in the polymer are due to units derived from 1-butene.

Ethylene-α-olefin copolymers of low molecular weight and containingresidual double-bond unsaturation have been prepared using a new type ofcatalyst comprising a metallocene and an alumoxane, as disclosed in thefollowing references.

U.S. Pat. No. 4,668,834 teaches ethylene-α-olefin copolymers andterpolymers having a M_(n) of between about 250 and about 20,000, aviscosity index of at least about 75, and a vinylidene-type terminalunsaturation. The patent also discloses that the molar ethylene contentof the copolymers is preferably in the range of between about 20 andabout 80, more preferably between about 30 and about 70%, and mostpreferably between about 35 and about 65%. The patent further disclosesthe preparation of these polymers via certain Group IV catalysts,particularly certain metallocenes, and aluminoxane co-catalysts.Propylene and 1-butene are specifically disclosed to be among thepreferred α-olefins for polymerization with ethylene. Theethylene-α-olefin copolymers and terpolymers are disclosed to be usefulas intermediates in epoxy-grafted electrical encapsulation compositions.The patent contains examples directed to the preparation andepoxy-grafting of ethylene-propylene copolymers, but not ofethylene-1-butene (EB) copolymers. The use of these polymers to prepareashless dispersants containing nitrogen is not disclosed.

U.S. Pat. No. 4,704,491 relates to liquid ethylene-α-olefin randomcopolymers, useful when hydrogenated as synthetic lubricant oil,characterized inter alia by having 10-85 mole % (=5-74 wt. %),preferably 20-80 mole % (=11-67 wt. %), most preferably 30-70 mole %(=17-54 wt. %) ethylene units; 15-90 (preferably 20-80, most preferably30-70) mole % α-olefin units; M_(n) of from 300 to 10,000; a M_(w)/M_(n) of not more than 2.5; and an iodine value in the range of 0 to85. The copolymers are also characterized by a B value of at least 1.05but not more than 2, wherein the B value is an index showing the stateof distribution of monomer components in the copolymer chain and isdefined as P_(OE) /(2P_(O) *P_(E)), wherein P_(E) is the molar fractionof ethylene component in the copolymer, P_(O) is the molar fraction ofthe α-olefin component in the copolymer, and P_(OE) is the molarfraction of α-olefin-ethylene chains in the total dyad chains. Thepatent discloses the B value may be determined from the C-13 NMRspectrum of the copolymer. The patent states that the liquid copolymercan be easily modified since it has a double bond capable of reactingwith maleic anhydride, etc., at the molecular chain ends.

The patent further discloses that these copolymers can be produced bycopolymerizing ethylene and a C₃ -C₂₀ α-olefin in the presence of acatalyst comprising a group IVb transition metal compound, such as ametallocene, and an aluminoxane. In addition to numerous examplesdirected to EP copolymers, the patent provides two examples of thepreparation of EB copolymers by the polymerization of ethylene and1-butene in the presence of zirconocene-aluminoxane catalyst systems.Example 6 discloses an EB copolymer having an ethylene content of 55mole % (=38 weight percent) and an M_(n) of 1200. Example 14 disclosesan EB copolymer with 60 mole % ethylene (43 wt %) and M_(n) of 2300.

PCT Published Application WO 90/1,503 is directed to ethylene-α-olefinpolymers which have a molar content of ethylene of from about 20 toabout 80 percent (=11-67 wt. %), preferably about 30 to about 70 percent(=17-54 wt. %), most preferably about 45 to about 65 percent (=29-48 wt.%); a number average molecular weight of from about 300 to about 10,000;and in which at least 90% of all polymer chains contain at least onecarbon-carbon double bond and exhibit a ratio of vinylidene to vinyldouble bonds of at least 3.5 to 1. It is disclosed that the polymers canbe prepared by polymerization of ethylene and the α-olefin using certainmetallocene-alumoxane catalysts and by using certain procedures andconditions. Example 5 discloses the preparation of an EB copolymer withM_(n) of 860 using dimethylsilyldicyclopentadienyl zirconium dichlorideand methylalumoxane. The remaining preparative examples are directed toEP copolymers.

U.S. Pat. No. 5,043,515 teaches a zirconocene/aluminoxane catalyst foroligomerizing olefins and the oligomerization process using thecatalyst. More particularly, the patent discloses the oligomerization ofethylene or ethylene with one or more C₃ -C₁₀ α-olefins using thecatalyst. It is further disclosed that, when the starting material isethylene in combination with one or more α-olefins, the product olefins(i.e., the oligomers) contain significant portions of vinylideneolefins. Example 3-5 of the patent describes the oligomerization ofethylene and 1-butene using bis(cyclopentadienyl)zirconium dichlorideand aluminoxane. The oligomers are disclosed to be useful asintermediates in preparing specialty detergents or lubricant additives.

The following references also disclose metallocene-alumoxane-prepared,low-molecular-weight ethylene-α-olefin copolymers, but are primarilydirected to the chemical modification of the copolymers to provideadditives for lubricating oils.

U.S. Pat. No. 4,981,605 relates to liquid epoxidized ethylenic randomcopolymers and to liquid hydroxylated ethylenic random copolymers, bothof which are useful as lubricant oil additives, paint additives, andresin modifiers. The patent discloses that the epoxidized/hydroxylatedethylenic random copolymer is an epoxidation/hydroxylation product of aliquid ethylenic random copolymer of ethylene and a C₃ -C₂₀ α-lefin,wherein the epoxy/hydroxyl groups are each formed via a carbon-carbonunsaturated bond derived from ethylene or the α-olefin and positioned atthe polymer chain end of the liquid ethylenic random copolymer. Thepatent further discloses that the liquid ethylene random copolymer hasinter alia an ethylene component content of 10-85 mole %, an α-olefincontent of 15 to 90 mole %, a M_(n) of usually 200 to 10,000, and amolecular weight distribution of usually not more than 4.0. ReferentialExample 6 discloses the preparation of a liquid EB random copolymer withan ethylene content of 58 mole % (41 wt %) and M_(n) of 1500 bypolymerization of ethylene and 1-butene in the presence ofbis(cyclopentadienyl) zirconium dichloride and aluminoxane.

European Published Patent Application 353,935 A1 is directed tooil-soluble lubricating oil additives comprising at least one terminallyunsaturated ethylene-α-olefin polymer having a number average molecularweight of 300 to 10,000 substituted with mono- or dicarboxylic acidproducing moieties, wherein at least about 30 percent of the polymerchains of the ethylene-α-olefin polymer possess terminal ethenylideneunsaturation. European Published Patent Application 441,548 A1 providessimilar teachings for terminally unsaturated ethylene-α-olefincopolymers having number average molecular weights from about 300 to20,000. EP 353,935 A1 further discloses that the monocarboxylic acid andthe dicarboxylic acid or anhydride substituted polymers can be furtherreacted with a nucleophilic reagent such as amines, alcohols, aminoalcohols and metal compounds, to form derivatives useful as lubricatingoil additives such as dispersants. Suitable ethylene contents for theethylene-α-olefin polymers are disclosed to range from 20 to 80,preferably 30 to 70, and most preferably 45 to 65 mole %. Example 5discloses the preparation of an EB copolymer of M_(n) of 860 usingdimethylsilyldicyclopentadienyl zirconium dichloride andmethylalumoxane. The ethylene content of the polymer is not disclosed inthe Example. The subsequent functionalization of the polymer to anEB-substituted succinic anhydride (EBSA), and the derivatization of theEBSA with an amido amine are also exemplified.

U.S. Pat. No. 4,943,658 discloses liquid oxidatively modified ethylenicrandom copolymers, useful as formulating agents for lubricant oils,wherein the liquid ethylenic random copolymer comprises 20-80 mole % ofethylene and 80-20 mole % of α-olefin and has a number average molecularweight of from 200 to 10,000 and a molecular weight distribution in therange of up to 4. The examples are directed to the modification of EPcopolymers.

U.S. Pat. No. 5,017,299 is directed to oil-soluble lubricating oiladditives comprising Mannich Base condensates of an alkyl substitutedhydroxy aromatic compound with formaldehyde and an amine, wherein thealkyl moiety of the aromatic compounds is derived from at least oneethylene-α-olefin copolymer of 300 to 10,000 number average molecularweight and wherein at least about 30% of the polymer chains containterminal ethenylidene unsaturation.

While many of the above described metallocene-derived ethylene-α-olefinpolymers can be successfully employed to make ashless dispersants, ithas been found that further improvements in the performance of ashlessdispersants incorporating such polymers, as well as significantimprovements in the economics of the dispersants can be achieved byselectively controlling, for example, the monomer identity, monomercontent, and certain polymer properties, within the broad general classof ethylene-α-olefin copolymers.

SUMMARY OF THE INVENTION

The present invention is directed to copolymers derived from ethyleneand 1-butene (alternatively referred to as ethylene-1-butene copolymersor, more simply, EB copolymers) which can be characterized by a complexset of properties, such as having a number average molecular weightbetween about 1,500 and 7,500, having at least about 30% of all polymerchains terminated with ethylvinylidene groups, having an ethylenecontent of not greater than about 50 weight percent, and formingsolutions in mineral oil which are free of polymer aggregates, asindicated by light scattering measurements. More particularly, the EBcopolymers of the invention are characterized by forming mineral oilsolutions which have values of about zero for their light scatteringfactor, S_(f), as hereinafter defined. The S_(f) value of about zeroexhibited by these solutions shows that there is an absence ofassociation or aggregation between individual EB polymer moleculesdissolved in the mineral oil solutions. These aggregation-free mineraloil solutions of the EB copolymers of the invention may alternatively bereferred to as homogeneous mineral oil solutions.

This combination of a relatively limited range of properties yields EBcopolymers of the invention especially suitable for use as polymerbackbones in lubricating oil additives, particularly dispersantadditives. The limited range of number average molecular weightscharacterizing the EB copolymers of the present invention ensures thatdispersants produced from the copolymers are fully solubilized inlubricating base oils, and at the same time assists in avoiding orreducing handling problems due to high viscosity levels and wax crystalinteractions. Because of the relatively high level of terminalethylvinylidene unsaturation in the inventive EB copolymers, thedispersant additives produced therefrom have high active ingredientconcentrations, thereby providing enhanced lubricating oil dispersancy,as exhibited by enhanced sludge and varnish control properties.

Furthermore, the polymers of the present invention and the dispersantadditives produced therefrom possess enhanced pour point performance inlubricating oil compositions to which they are added and which alsocontain conventional LOFI's. This beneficial pour point behavior of thedispersants is believed to be attributable in part not only to theability of the EB copolymers to form homogeneous mineral oil solutionsfree of polymer aggregates as manifested by S_(f) values of about zero,but also to the limited ethylene content. In contrast, EB copolymerswith S_(f) values greater than zero and/or ethylene contents in excessof about 50 weight percent, and dispersant additives produced therefrom,can exhibit an increase in the pour point of lubricating oilcompositions in which they are used. Accordingly, in one of its aspects,this invention concerns lubricating oil compositions comprising a majoramount of a lubricating base oil, an effective amount of a lubricatingoil flow improver, and a minor amount of the EB copolymer of the presentinvention.

A further aspect of this invention relates to the ethylene-1-butenecopolymer functionalized with reactive groups, such as by substitutionwith mono- or dicarboxylic acid materials (i.e., acid, anhydride or acidester) produced by reacting (e.g., by the "ene" reaction) the EBcopolymers of the invention with mono-unsaturated carboxylic reactants.The monocarboxylic acid and the dicarboxylic acid or anhydridesubstituted EB copolymers are useful per se as additives to lubricatingoils, and, in another aspect of this invention, can also be reacted withnucleophilic reagents, such as amines, alcohols, amino alcohols andmetal compounds, to form derivative products which are also useful aslubricating oil additives, e.g., as dispersants.

In still another aspect of this invention, lubricating oil additives areproduced by functionalizing the EB copolymers of the invention usingreactants other than the mono-unsaturated carboxylic reactantsheretofore described. Accordingly, the copolymer can be functionalizedby reaction with a hydroxy aromatic compound in the presence of acatalytically effective amount of at least one acidic alkylationcatalyst. Subsequently the alkylated hydroxyaromatic compound can bereacted by Mannich Base condensation with an aldehyde and an aminereagent to provide a derivatized copolymer.

Lubricating oil additives within the scope of this invention are alsoproduced by oxidation of the EB copolymer of the invention, such asoxidation with a gas containing oxygen and/or ozone. The copolymer canalso be functionalized by hydroformylation and by epoxidation. The EBcopolymers can also be functionalized by contacting the copolymers underKoch reaction conditions with carbon monoxide in the presence of anacidic catalyst and a nucleophilic trapping agent such as water or ahydroxy-containing compound or a thiol containing compound to formcarboxyl groups on the polymer. Furthermore, the aforesaidfunctionalized polymers formed by oxidation, hydroformylation,epoxidation, and Koch reaction can be derivatized by reaction with atleast one derivatizing compound to form derivatized polymers.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 provides a schematic comparison of the light scattering behaviorof the EB polymer of the invention with another EB polymer.

FIG. 1-A is a graphical plot of the scattered light intensity for asolution of the EB polymer of the present invention in S150NL mineraloil as a function of the time which has elapsed following the quenchingof the solution from a temperature of about 80° C. or higher to 20° C.,wherein the EB polymer forms a homogeneous solution with an absence ofaggregates following the quench.

FIG. 1-B is a comparative graphical plot of scattered light intensitydata for a S150NL mineral oil solution of an EB polymer which does forma solution containing aggregates following the quench.

FIG. 2 is a plot of the pour points of the EB copolymers in Table IV asa function of their ethylene contents in weight percent. The diameter ofthe circle marking the pour point of a given copolymer is proportionalto its number average molecular weight. The number associated with eachcircle is the sample number assigned to the copolymer in Table IV.

FIG. 3 provides graphical plots of the scattered light intensity fromsolutions of EB polymer in S150NL mineral oil as a function of the timewhich has elapsed following the quenching of the solution from atemperature of about 80° C. to 201° C.

FIG. 3-A is a plot of the light scattering data for a sample of the EBcopolymer prepared in Example 1, and

FIG. 3-B is a plot of the light scattering data for a sample of the EBcopolymer prepared in Comparative Example 2.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to copolymers derived from ethylene and1-butene characterized by a certain combination of chemical and physicalproperties which makes the copolymers especially suitable for use as thebackbones of dispersant additives. More particularly, the EB copolymersof the invention possess a relatively high degree of terminal vinylideneunsaturation, a number average molecular weight within a limited range,controlled ethylene content, and the ability to form mineral oilsolutions which have an absence of polymer aggregation. Each of theseproperties contributes in one or more respects to the utility of thecopolymer as a dispersant backbone.

The EB copolymers of this invention possess a high degree of terminalvinylidene-type unsaturation. The EB copolymers of this invention havepolymer chains of formula POLY--C(--CH₂ CH₃)═CH₂, wherein POLYrepresents the polymer chain and the --C(--CH₂ CH₃)═CH₂ represents anethylvinylidene group terminating one end of the chain. The EBcopolymers typically have ethylvinylidene groups terminating at leastabout 30 percent of the polymer chains. More preferably, ethylvinylidenegroups terminate at least about 50 percent of the polymer chains, andmost preferably ethylvinylidene groups terminate at least about 65percent of the polymer chains, and typically from about 50 to 75%. Inaddition, the copolymers typically have vinyl groups (i.e.,POLY--CH═CH₂, where --CH═CH₂ is vinyl) terminating no more than about 10percent of the chains and internal mono-unsaturation in the balance ofthe chains. The internal mono-unsaturation typically includes vinylenes(i.e., POLY--CH═CH(--CH₃), where the methyl may be cis or trans to POLY)in amounts between about 1 to 8% based upon total polymer unsaturationand trisubstituted vinyls in amounts between about 20 and 50 percent.The percentage of polymer chains exhibiting terminal ethylvinylideneunsaturation, terminal vinyl unsaturation, etc. may be determined byFTIR spectroscopic analysis, titration, or by C-13 NMR. It will beunderstood that a change in the type of metallocene catalyst orco-catalyst used to prepare the polymer (see discussion infra) can shiftthe above described double bond distribution to some extent. Because ofthe relatively high level of terminal ethylvinylidene unsaturation inthe EB copolymers, the dispersant additives produced therefrom have highactive ingredient concentrations, thereby providing enhanced lubricatingoil dispersancy, as exhibited by enhanced sludge and varnish controlproperties.

The copolymers of this invention have a number average molecular weight(M_(n)) of typically from about 1,500 to about 7,500, preferably fromabout 1,500 to 6,000 (e.g., 1,500-5,000), and most preferably from about2,000 to 5,000 (e.g., 2,200 to 4,000).

With regard to composition, the EB copolymer will typically contain notgreater than about 50, preferably not greater than about 45, and mostpreferably not greater than 40 weight percent ethylene, based upon thetotal polymer weight. Thus, the ethylene content can range typicallyfrom about 1 to about 50 (e.g., from 5 to about 50) weight percent,preferably from about 5 to about 45 (e.g., 5 to about 35) weightpercent, and most preferably from about 10 to about 35 (e.g., 10 toabout 30) weight percent. The balance of the copolymer content issubstantially based upon units derived from 1-butene. Thus, the 1-butenecontent is typically from about 99 to 50 (e.g., 95 to about 50) weightpercent, preferably from about 95 to about 55 (e.g., 95 to about 65)weight percent, and most preferably from about 90 to 65 (e.g., 90 toabout 70) weight percent.

The copolymers of this invention may optionally contain small amounts(e.g., typically up to about 10, preferably up to about 5 weightpercent) of units derived from other α-olefins and C₃ to C₂₂ diolefins.In particular, introduction of small amounts of other C₄ olefins canresult during the preparation of the EB copolymers through the use of1-butene reactant streams which also contain certain amounts of2-butene, isobutene, and/or butadiene, as described in more detail inthe Section entitled "Preparation of the Ethylene-1-Butene Copolymer".

The EB copolymers of the invention also form mineral oil solutionshaving an absence of aggregation. By mineral oil solutions having anabsence of aggregation is meant an absence of association betweenindividual EB copolymer molecules dissolved in S150NL mineral oil at lowconcentration, typically about 5 wt. %. More particularly, the EBcopolymers of the invention form mineral oil solutions with an absenceof aggregation at 20° C. after quenching of the solutions from atemperature of about 80° C. or higher. That the solutions formed onquenching to 20° C. do indeed have an absence of aggregation, and arethus homogeneous, is determined by their light scattering behavior,wherein these solutions have a value of about zero for their lightscattering factor S_(f).

EB copolymers of the present invention which form homogeneous solutionswith an absence of aggregation generally exhibit one or more beneficialor improved properties pertinent to their use in lubricating oilsrelative to those EB copolymers which exhibit aggregation. Furthermore,when the polymers of the present invention are used as polymer backbonesin lubricating oil additives, particularly dispersant additives, thebeneficial or improved properties of the polymer are imparted to theadditive. For example, as described more fully below, thenon-aggregating nature of the EB copolymers of the invention is asufficient condition for the acceptable pour point performance of thecopolymers in mineral lubricating oils and for the acceptable pour pointperformance of additives obtained by functionalization or derivatizationof the copolymers.

The State of Aggregation in Mineral Oil Solutions of EBCopolymers--Characterization by Light Scattering

The state of aggregation of an EB copolymer in a mineral oil solution at20° C. is determined from the value of its scattering factor S_(f), asgiven by the following equation

    S.sub.f =(I.sub.eq -I.sub.o)/I.sub.o                       (I)

In equation (I), I_(o) is the average initial intensity of the lightscattered from a solution comprising from about 1 to 10 weight percent,typically about 5 weight percent, of the EB copolymer in S150NL (solvent150 neutral light) mineral lubricating oil (Exxon Company U.S.A.)immediately after the solution has been quenched from a temperature ofabout 80° C. or higher to a temperature of 20° C. 10 is determined fromthe measurement of the scattered intensity at time t=0; i.e.,immediately following the quench. I_(eq) is the average intensity of thelight scattered from the same solution, maintained at 20° C., after theelapse of at least a time t=t_(eq) following the quench. As describedmore fully below, t_(eq) is the time sufficient for the solution toachieve a constant (or "equilibrium") value of scattered light intensityfollowing the quench.

The EB copolymers of the invention have a value of about zero for S_(f),which means that the values for I_(eq) and 10 are essentiallyequivalent. In other words, the average intensity of the light scatteredfrom a solution of about 1 to 10 wt. % of an EB copolymer of theinvention in S150NL oil, measured while maintaining the solution at atemperature of 20° C. after first quenching from a temperature of about80° C. or higher, does not change over the elapsed time following thequench.

In contrast, EB copolymers having a tendency to aggregate in mineral oilsolutions have an S_(f) of greater than zero. For a solution comprisingabout 1 to 10 weight percent of such an aggregating EB copolymer inS150NL oil, the average intensity of the light scattered from thesolution is greater for times t equal to or greater than t_(eq)following the quenching of the solution from about 80° C. or higher to20° C. than the average intensity immediately following the quench attime t=0.

FIG. 1 provides a schematic comparison of the light scattering behaviorof the EB copolymers of the invention with EB copolymers which haveS_(f) greater than zero. FIG. 1-A is a plot of the scattered lightintensity in arbitrary units for a solution of the inventive EBcopolymer in S150NL mineral oil at 20° C. as a function of the timeelapsed since the quench. While there are random fluctuations in themeasured values of the scattered intensity due to background noise, theaverage scattered intensity does not change with elapsed time. Thus,I_(o) =I_(eq), and S_(f) =0.

FIG. 1-B is a plot analogous to FIG. 1-A, showing the scattered lightintensity as a function of post-quench time for a solution of an EBcopolymer having S_(f) greater than zero. For a relatively short periodof time immediately following the quench, the average scattered lightintensity has a relatively low and constant value, essentially equal toI_(o), the intensity at time t=0. There follows a time period in whichthe scattered light intensity measurably increases, shown in FIG. 1-B asthe interval of time from t' up to t_(eq). For the times greater orequal to t_(eq), the average scattered intensity has a relatively highand constant (or "equilibrium") value, equal to I_(eq). Thus, I_(eq)>I_(o), and S_(f) >0.

As noted earlier, the difference between the light scattering behaviorof the EB copolymers of the invention, which have S_(f) =0, and that ofEB copolymers which have S_(f) greater than zero is related to thedegree of aggregation (also called self-association) of the copolymersin the S150NL mineral oil solution. It is known by those skilled in theart of polymer light scattering that, for a constant intensity of lightincident on a dilute polymer solution which is maintained at a constanttemperature and which has a fixed concentration (e.g., a fixed weight ofsolute per volume of solution), the scattered light intensity measuredat a given scattering angle θ increases as the molecular weight of thepolymer increases. See, e.g., the discussion on pages 201-210 in Chapter8 of Chu, Benjamin, Laser Light Scattering, Academic Press, New York,1974, and the discussion on pages 198-202 of Billmeyer, Fred W.,Textbook of Polymer Science, John Wiley & Sons, New York, 1984. It isalso known that, if the individual polymer molecules in a dilutesolution aggregate in the solution, the scattered light intensity of thesolution would be higher for a given concentration than it would be inthe absence of the aggregation, due to the increase in the size of thescattering particles, or, in other words, due to an increase in the"apparent" molecular weight of the polymer particles. See, e.g., Elias,H. -G., "The Study of Association and Aggregation Via Light Scattering,"Chapter 9 in Huglin, M. B., editor, Light Scattering from PolymerSolutions, Academic Press, New York, 1972.

In terms of aggregation, then, the light scattering behaviors describedabove for mineral oil solutions of EB copolymers are accounted for asfollows: For both EB copolymers of the invention and for EB copolymershaving S_(f) greater than zero, solutions comprising about 1 to 10weight percent EB copolymer in S150NL mineral oil in equilibrium attemperatures of 80° C. or higher are essentially free of aggregation. Onthe other hand, solutions of EB copolymers having S_(f) greater thanzero contain aggregated EB copolymers in equilibrium at temperatures ofabout 20° C., but solutions of the EB copolymers of the invention remainfree of aggregation. Thus, when a solution comprising an EB copolymerhaving S_(f) greater than zero in S150NL mineral oil is suddenlyquenched from equilibrium at 80° C. or higher to a temperature of 20°C., the solution will initially contain unaggregated EB copolymermolecules in a quasi-stable condition. After the elapse of a timet_(eq), the solution will reach thermal equilibrium at 20° C. and themolecules, having had sufficient time to interact with one another, willhave formed polymer aggregates. Applying the light scattering principlesdescribed in the previous paragraph, the scattered light intensity ofthis solution for times t_(eq) and longer will be greater than theintensity at time t=0, based upon the increase in the apparent molecularweight of the copolymer molecules for times t_(eq) and longer due toaggregation.

On the other hand, analogous measurements of scattered light intensityas a function of time for quenched S150NL mineral oil solutions of theinventive EB copolymers manifest no changes in scattered lightintensity, since the inventive copolymer molecules do not aggregate inS150NL mineral oil after quenching the solution from 80° C. to 20° C.and therefore have no net change in apparent molecular weight.

It is important to point out that factors in addition to the formationof aggregates can in principle contribute to a change in the scatteredlight intensity of a polymer solution upon quenching. In particular,scattering intensity is a function of the specific refractive indexincrement of a polymer solution, dn/dc=the change in the refractiveindex of a solution with the change in polymer concentration, the valueof which is temperature dependent. It has been found here, however, thatthe scattering contribution due to the temperature dependence of dn/dcis negligible relative to that attributable to polymer aggregation.

As should be clear from the above discussion, values of t_(eq) forsolutions of EB copolymers having S_(f) greater than zero isdeterminable from, and indeed fixed by, the plot of scattered lightintensity versus time. In measuring 10 and I_(eq) for these cases, theactual value of t_(eq) is used. t_(eq) is typically at least about 5minutes and generally no more than about 15 to 20 min. In a typicalexperiment, the scattered light intensity is measured several times perminute for up to at least about 60 to 120 min. Taking measurements forthese extended periods of time insures that EB copolymers havingunusually long t_(eq) 's (e.g., about 30 minutes) are not missed.

On the other hand, for solutions of the EB copolymer of the invention,it is neither possible nor necessary to determine the actual value oft_(eq) from the plot of scattered light intensity versus post-quenchingtime, because the average scattering intensity does not change withtime. Thus, in measuring I_(eq) here, any convenient, arbitrarily chosenvalue of t_(eq) may be used; e.g., about 15 minutes. (Note, however,that measurements should be taken for at least 30 minutes folowing thequench to insure the particular copolymer under test is not anaggregating copolymer with an unusually long t_(eq).)

Values for I_(o) and I_(eq) may be measured using conventional elasticlight scattering techniques, the practice of which has been described ina number of publications including Huglin, M. B., editor, LightScattering from Polymer Solutions, Academic Press, New York, 1972;Kerker, Milton, The Scattering of Light and Other ElectromagneticRadiation, Academic Press, New York, 1969; and Chu, Benjamin, LaserLight Scattering, Academic Press, New York, 1974; and Berry, Guy C.,"Light Scattering," in Encylopedia of Polymer Science and Engineering,volume 8, 2nd edition, John Wiley & Sons, New York, 1987, pages 721-794.For the purposes of this invention, the critical determination iswhether or not a change occurs in the scattered light intensity, asdefined by S_(f) in equation (I), as a function of time. Thus, it is notnecessary to measure the scattering against a calibration standard or tootherwise determine the intensity in absolute terms.

In a typical light-scattering photometer useful for measuring I_(o) andI_(eq), a monochromatic beam of light emitted from a laser is directedinto the sample cell containing the EB copolymer solution. The lightscattered from the copolymer solution at a scattering angle θsubsequently passes through certain detector optics, finally reaching aphotomultiplier PM which, in combination with a data acquisition systemDAS, provides an output signal that is a function of the scattered lightintensity. Depending upon the choice of PM and DAS, the output signalmay be either an analog signal or a count of the scattered photons.

Because it produces a relatively high intensity, monochromatic beam oflight, a laser is the preferred light source in a light-scatteringphotometer. The laser may have Brewster windows or the equivalent (e.g.,a Nicol prism placed in the path of the beam emitted from laser) inorder to provide a polarized light beam incident on sample cell, but apolarized light source is not necessary. The laser may be any lasercapable of emitting light radiation. Suitable lasers include, but arenot limited to, He--Ne lasers emitting at 632.8 nm and Ar lasersemitting at either 548 nm or 488 nm.

Careful sample preparation is critical to the accurate measurement ofI_(eq) and I_(o). Most particularly, the presence of dust or otherextraneous material in the EB copolymer solution must be avoided, sinceit could otherwise contribute significantly to the scattering and leadto indeterminate or erroneous results. Thus, the solution is typicallycentrifuged or filtered or both just prior to any scatteringmeasurements. It is also important to completely dissolve the polymer inthe oil to avoid scattering contributions due to solutioninhomogeneities. Complete dissolution is typically accomplished by usinga combination of vigorous mixing of the polymer with the oil, followedby heating the mixture to a high temperature and maintaining thesolution at that high temperature until dissolution is complete.

A preferred method of sample preparation involves adding to a suitableportion of S150NL mineral oil the amount of EB copolymer necessary toproduce the desired concentration of the polymer in the oil (i.e., about1 to 10 weight percent, typically 5 weight percent), agitating thepolymer-oil combination for several hours, and then heating thepolymer-oil mixture to a temperature of about 80 to 90° C. andmaintaining the mixture at that high temperature with occasional shakinguntil dissolution is complete. The solution is then maintained at about80° C. or higher for several more hours, and then filtered directly intothe sample cell. The resulting dust-free solution still at about 80° C.or higher is then immediately quenched by placement in the sampleholder, thermostatted at 20° C., of the light scattering photometer, andthe scattering intensity from the solution is monitored as a function oftime in the manner already described.

Preferred EB copolymers of the invention may be further characterized bypour points of about -30° C. or less, as determined by ASTM Method No.D97, wherein the measurements are made upon solutions comprising 2weight percent of the EB copolymer of the invention and 0.2 weightpercent of a conventional lube oil flow improver comprising a C₈ -C₁₈dialkyl fumarate-vinyl acetate copolymer in S150NL mineral lubricatingoil. As noted earlier, the pour point of an oil composition is thelowest temperature at which it will flow when chilled in a specificmanner; here, the manner prescribed by ASTM Method No. D97. Desirablelubricating oil compositions typically have a relatively low pour point,typically about -30° C. or less.

A requirement of any dispersant additive is that it not adversely affect(i.e., does not significantly increase) the pour point of thelubricating oil composition to which it is added. It has been found thatthe pour point behavior of dispersant additives is largely determined bythe pour point behavior of the polymer from which they are derived. Moreparticularly, it has been found that, if an EB copolymer in solutionexhibits a pour point of about -30° C. or less, as determined accordingto the method described in the last paragraph, the addition to alubricating oil composition of an effective amount of a dispersantadditive produced by the functionalization and/or derivatization, ashereinafter described, of the EB copolymer does not significantly alterthe pour point of the composition.

The pour point behavior exhibited by a given EB copolymer is related towhether or not it forms aggregates in mineral oil solutions, as definedsupra in terms of light scattering. The EB copolymers of the invention,which have S_(f) values of about zero and thus a tendency not to formaggregates, exhibit pour points of about -30° C. or less. It isemphasized, however, that, while absence of aggregation as determined byS_(f) has been found to be a sufficient condition for satisfactory pourpoint, it has not been found to be a necessary condition. It is not anecessary condition, because, though some EB copolymers with S_(f)values greater than zero (i.e., a tendency to form aggregates) exhibithigh pour points of greater than about -30° C., other EB copolymers withS_(f) values greater than zero may nonetheless have pour points belowabout -30° C.

Among the other factors implicated in pour point performance are theethylene content and the number average molecular weight of the polymer.FIG. 2 plots the pour points, measured as described in the second tolast paragraph, of a series of EB copolymers having ethylene contentsranging from 15 to 62 wt. % and number average molecular weights rangingfrom 1,627 to 12,432. These copolymers, some within the scope of thepresent invention and some not, were all prepared using the catalystsand processes as generally described in the section entitled"Preparation of the Ethylene-1-Butene Copolymer." Based on the datashown in FIG. 2, it has been concluded that an EB copolymer which has anethylene content of less than about 50 weight percent and an M_(n) of upto about 7,500 can be expected to have acceptable pour point behavior.It has also been concluded that a polymer which has an ethylene contentabove about 60 weight percent and M_(n) above about 10,000 can beexpected to have unacceptable pour point behavior. However, the pourpoint behavior of polymers having ethylene contents in the range fromabout 50 to 60 wt. % appear to be unpredictable. For example, polymersample number 16 (51 wt. % ethylene and M_(n) =2,844) has a pour pointof -36° C., but polymer sample number 15 (50 wt. % ethylene and M_(n)=3,370) has a pour point of -18° C. Thus, it is believed that the 50-60wt. % range of ethylene content represents a discontinuous transitionalrange, wherein it is possible to achieve good pour point behavior, butnot on a predictable basis.

It should be clear, in view of FIG. 2, that the advantages of the EBcopolymers of the present invention over other EB copolymers depend to adegree upon the range(s) of ethylene content and/or Mn in which theother polymers lie. The present invention is directed to EB copolymerswhich have an ethylene content of not greater than about 50 wt. %, anumber average molecular weight of up to about 7,500, and a tendency notto form aggregates in mineral oil solutions, as indicated by an S_(f)value of about zero. The advantage of the EB copolymers of the presentinvention over EB copolymers which have ethylene contents above about 50wt. % (regardless of M_(n)) is the predictably acceptable pour pointperformance of the inventive copolymer. The advantage of the EBcopolymers of the present invention over other EB copolymers which haveethylene contents below about 50 wt % and M_(n) up to about 7,500 (andthus acceptable pour points) is the absence of aggregation in mineraloil solutions of the inventive copolymer. It is believed that thisabsence of aggregation exhibited by the EB copolymers of the presentinvention generally results in more predictable and less adverseinteractions between the copolymers (and their functionalized andderivatized counterparts) and the mineral oil (e.g., interactions withthe wax component of the mineral oil), relative to EB copolymers havingethylene contents and number average molecular weights in the samerange, but exhibiting aggregation, as indicated by their non-zero S_(f)values.

The EB copolymers of the invention preferably also have an averageethylene sequence length (ESL) of from about 1 to 2.50. ESL is the ratioof the total number of ethylene units in the copolymer chains to thetotal number of discrete ethylene sequences in the copolymer chains, asgiven by the following equation (II):

    ESL=(X.sub.EEE +X.sub.BEE+EEB +X.sub.BEB)/(X.sub.BEB +0.5*X.sub.BEE+EEB)(II)

wherein X_(EEE) is the mole fraction of ethylene-ethylene-ethylene triadsequences in the copolymer; X_(BEE+EEB) is the mole fraction ofbutene-ethylene-ethylene and ethylene-ethylene-butene triad sequences;and X_(BEB) is the mole fraction of butene-ethylene-butene triadsequences. The ESL value is an index reflecting the distribution of theunits derived from ethylene in the ethylene-1-butene copolymer chains.As the value for ESL increases for a given EB copolymer of fixedethylene content, the number of isolated ethylene units in the chainsdeclines, and, concomitantly, the number of ethylene units per ethylenesequence increases. Naturally, as the ethylene content increases in anEB copolymer containing even a random distribution of ethylene units,the general tendency is to obtain increased ESL values.

As per equation (II), the ESL value of an EB copolymer can be calculatedfrom X_(EEE), X_(BEE+EEB), and X_(BEB), which are determined from thepolymer's C-13 NMR spectrum, using the methods described in, forexample, Randall, James C., Journal of Macromolecular Science--Reviewsof Macromolecular Chemistry and Physics, C29, 201-317 (1989), and inHsieh, Eric T. and Randall, James C., Macromolecules, 15, 353-360(1982).

While not wishing to be bound by any particular theory, it is believedthat the relatively low ESL values of the EB copolymers of the inventionestablish, at least in part, the structural basis for the absence ofaggregation in the 1-10 weight percent mineral oil solutions of thesecopolymers at 20° C., as discussed supra with respect to the lightscattering behavior of the copolymers. It is believed that aggregationoccurs in EB copolymers which have long crystalline-like ethylenesequences in the chains, wherein the sequences in one polymer chain actas the sites for aggregation with similar crystalline-like ethylenesequences in the other chains. The relatively low ESL values of theinventive EB copolymers point to a relative absence of longcrystalline-like ethylene sequences in the copolymer molecules, and thusto an absence of aggregation sites. On the other hand, EB copolymerswith S_(f) values greater than zero have relatively high ESL values,indicating that they have one or more relatively long crystalline-likeethylene sequences in most or all of their copolymer chains, and,therefore, have a tendency to aggregate. (Note: An important assumptionunderlying this discussion is that the total ethylene content in thecopolymer is above the threshold amount necessary to allow formation ofa concentration of ethylene segments sufficient to affect theaggregative behavior of the copolymer as a whole. It is possible, evenat very low ethylene content, to produce a copolymer having a high valueof ESL, but which, because so few ethylene segments are present on anabsolute basis, will not affect aggregation behavior.).

It is believed that other types of crystallinity that may be present inthe copolymer, either in addition to or as a substitute for ethyleniccrystallinity, play little or no role in polymer aggregation. Thus,random EB copolymers with low ethylene content (e.g., no more than about5 wt. %) and virtually no ethylenic crystallinity have S_(f) values ofabout zero, even though these copolymers may have substantial isotacticcrystallinity due to the presence of relatively long isotactic sequencesderived from 1-butene in most or all of the copolymer chains; sequenceswhich arguably could act as aggregation sites. Interestingly, it hasbeen found that isotactic 1-butene homopolymers also have S_(f) valuesof about zero, which is consistent with the theory that isotacticcrystallinity has no role in determining whether or not an EB copolymerwill aggregate in mineral oil solutions.

The relatively low ESL values of the EB copolymers of the invention alsopoint to a structural basis for the pour point behavior of the EBcopolymers of the invention, and thus for the dispersant additivesfunctionalized and/or derived therefrom. As a lubricating oil is cooled,wax in the oil precipitates into crystals which form a network. As notedearlier in the section entitled "Background of the Invention," the pourpoint of the oil is marked by the temperature at which the fluidcomponent of the oil is immobilized by the wax crystal network. Becausethe EB copolymers of the invention have a minimized content of longcrystalline-like ethylene sequences (i.e., minimized wax-likecharacter), the copolymers' participation in the formation of the waxcrystal network is also minimal, along with their impact on the pourpoint of the oil.

By contrast, with respect to those EB copolymers with S_(f) valuesgreater than zero and with high pour points, the copolymers havesufficiently long crystalline-like ethylene sequences, such that theyincrease the pour point of the oil by participating in the formation ofthe wax crystal network in a disadvantageous manner as the oil cools.

As to those EB copolymers with S_(f) values greater than zero, but whichnonetheless have acceptable pour point, it appears that there is atransitional range of ethylene sequence lengths which are sufficient tocause aggregation of these copolymers, but which at the same time areeither insufficient to permit the copolymer to participate effectivelyin the formation of the wax crystal network or are sufficient to permitan interaction, but the interaction occurs in a beneficial manner,similar to the manner a LOFI beneficially controls wax interactions.

The copolymers of this invention preferably also have a molecular weightdistribution (MWD), defined as the ratio of the weight average molecularweight (M_(w)) to the number average molecular weight (i.e., MWD=M_(w)/M_(n)), of less than about 5, preferably less than about 4, and mostpreferably less than about 3. More specifically, the copolymers have amolecular weight distribution of from about 1.0 to about 3.5, and mostpreferably from about 1.1 to about 3. Both M_(n) and M_(w) can bedetermined by the technique of gel permeation chromatography (GPC) witha suitable calibration curve, from which MWD can be readily obtained.M_(n) and MWD for ethylene-α-olefin copolymers, for example, can beobtained using calibration curves based upon polydisperseethylene-α-olefin copolymers having ethylene contents similar to that ofthe samples under test. For a description of the determination of M_(n)and MWD using GPC (also known as size exclusion chromatography), see W.W. Yau, J. J. Kirkland and D. D. Bly, "Modern Size Exclusion LiquidChromatography", John Wiley and Sons, New York, 1979.

M_(n) can alternatively be determined for certain polymers such asethylene-α-olefin copolymers from either their proton- or carbon-13 NMRspectra obtained in solution, using conventional analytical techniquesknown to those skilled in the art. See, for example, "C13-NMR in PolymerQuantitative Analyses," J. C. Randall and E. T. Hiseh, in: NMR andMacromolecules. Sequence, Dynamic, and Domain Structure, ACS SymposiumSeries No. 247, 131-151 (Amer. Chem. Society, 1984).

Preparation of the Ethylene-1-Butene Copolymer

Ethylene-1-butene copolymers of the present invention which have arelatively high degree of terminal ethylvinylidene unsaturation can beprepared by polymerizing monomer mixtures comprising ethylene and1-butene in the presence of a catalyst system comprising at least onemetallocene (e.g., a cyclopentadienyl-transition metal compound) andpreferably an activator, e.g., an alumoxane compound. The termmetallocene refers to compounds containing a coordination bond between atransition metal and at least one cyclopentadiene ring structure. Theterm cyclopentadiene ring structure includes saturated or unsaturatedpolycyclic structures such as indenyl and fluorenyl which incorporate afive-membered ring. The co-monomer content can be controlled through theselection of the metallocene catalyst component and by controlling therelative proportions of the ethylene and 1-butene.

The preferred method and catalysts for preparing the EB copolymers aredisclosed in commonly assigned copending U.S. Ser. No. 992,690, filedDec. 17, 1992 (Docket No. PT-937), entitled "Dilute Feed Process for thePolymerization of Ethylene-α-Olefin Copolymer Using Metallocene Catalyst5 System," herein incorporated by reference.

The catalysts employed in the production of these EB copolymers areorganometallic coordination compounds which are cyclopentadienylderivatives of a Group 4b metal of the Periodic Table of the Elements(56th Edition of Handbook of Chemistry and Physics, CRC Press, 1975) andinclude mono-, di- and tricyclopentadienyls and their derivatives of thetransition metals. Particularly desirable are the metallocenes of aGroup 4b metal such as titanium, zirconium, and hafnium. The alumoxanesemployed in forming the reaction product with the metallocenes arethemselves the reaction products of an aluminum trialkyl with water.

In general, at least one metallocene compound is employed in theformation of the catalyst. As indicated supra, metallocene is a metalderivative of a cyclopentadiene. The metallocenes usefully employed inaccordance with this invention contain at least one cyclopentadienering. The metal is selected from the Group 4b preferably titanium,zirconium, and hafnium, and most preferably hafnium and zirconium. Thecyclopentadienyl ring can be unsubstituted or contain one or moresubstituents (e.g., from 1 to 5 substituents) such as, for example, ahydrocarbyl substituent (e.g., up to 5 C₁ to C₅ hydrocarbylsubstituents) or other substituents, e.g. such as, for example, atrialkyl silyl substituent. The metallocene can contain one, two, orthree cyclopentadienyl rings; however, two rings are preferred.

Useful metallocenes can be represented by the general formulas:

    (C.sub.p).sub.m MR.sub.n X.sub.q                           (III)

wherein C_(p) is a cyclopentadienyl ring, M is a Group 4b transitionmetal, R is a hydrocarbyl group or hydrocarboxy group having from 1 to20 carbon atoms, X is a halogen, and m is a whole number from 1 to 3, nis a whole number from 0 to 3, and q is a whole number from 0 to 3.

    (C.sub.5 R'.sub.k).sub.g R".sub.s (C.sub.5 R'.sub.k)MQ.sub.3-g(IV)

and

    R".sub.s (C.sub.5 R'.sub.k).sub.2 MQ'                      (V)

wherein (C₅ R'_(k)) is a cyclopentadienyl or substitutedcyclopentadienyl, each R' is the same or different and is hydrogen or ahydrocarbyl radical such as alkyl, alkenyl, aryl, alkylaryl, orarylalkyl radical containing from 1 to 20 carbon atoms, a siliconcontaining hydrocarbyl radical, or hydrocarbyl radicals wherein twocarbon atoms are joined together to form a C₄ -C₆ ring, R" is a C₁ -C₄alkylene radical, a dialkyl germanium or silicon, or a alkyl phosphineor amine radical bridging two (C₅ R'_(k)) rings, Q is a hydrocarbylradical such as aryl, alkyl, alkenyl, alkylaryl, or aryl alkyl radicalhaving from 1-20 carbon atoms, hydrocarboxy radical having from 1-20carbon atoms or halogen and can be the same or different from eachother, Q' is an alkylidene radical having from 1 to about 20 carbonatoms, s is 0 or 1, g is 0, 1 or 2, s is 0 when g is 0, k is 4 when s is1, and k is 5 when s is 0, and M is as defined above. Exemplaryhydrocarbyl radicals are methyl, ethyl, propyl, butyl, amyl, isoamyl,hexyl, isobutyl, heptyl, octyl, nonyl, decyl, cetyl, 2-ethylhexyl,phenyl and the like. Exemplary silicon containing hydrocarbyl radicalsare trimethylsilyl, triethylsilyl and triphenylsilyl. Exemplary halogenatoms include chlorine, bromine, fluorine and iodine and of thesehalogen atoms, chlorine is preferred. Exemplary hydrocarboxy radicalsare methoxy ethoxy, butoxy, amyloxy and the like. Exemplary of thealkylidene radicals is methylidene, ethylidene and propylidene.

Illustrative, but non-limiting examples of the metallocenes representedby formula III are dialkyl metallocenes such asbis(cyclopentadienyl)titanium dimethyl, bis(cyclopentadienyl)titaniumdiphenyl, bis(cyclopentadienyl)zirconiumdimethyl,bis(cyclopenta-dienyl)zirconiumdiphenyl, bis(cyclopentadienyl)hafniumdimethyl and diphenyl, bis(cyclopentadienyl)titanium di-neopentyl,bis(cyclopentadienyl)zirconium di-neopentyl, bis(cyclopentadienyl)titanium dibenzyl, bis(cyclopentadienyl) zirconium dibenzyl,bis(cyclopentadienyl)vanadium dimethyl; the mono alkyl metallocenes suchas bis(cyclopentadienyl)titanium methyl chloride, bis(cyclopentadienyl)titanium ethyl chloride bis(cyclopentadienyl)titanium phenyl chloride,bis(cyclo-pentadienyl) zirconium hydrochloride,bis(cyclo-pentadienyl)zirconium methyl chloride, bis(cyclopentadienyl)zirconium ethyl chloride, bis(cyclopentadienyl)zirconium phenylchloride, bis(cyclopentadienyl)titanium methyl bromide,bis(cyclopentadienyl) titanium methyl iodide,bis(cyclopentadienyl)titanium ethyl bromide,bis(cyclo-pentadienyl)titanium ethyl iodide,bis(cyclopenta-dienyl)titanium phenyl bromide, bis(cyclopentadienyl)titanium phenyl iodide, bis(cyclopentadienyl)zirconium methyl bromide,bis(cyclopentadienyl)zirconium methyl iodide, bis(cyclopentadienyl)zirconium ethyl bromide, bis(cyclopentadienyl)zirconium ethyl iodide,is(cyclopentadienyl)zirconium phenyl bromide,bis(cyclopentadienyl)zirconium phenyl iodide; the trialkyl metallocenessuch as cyclopentadienyltitanium trimethyl, cyclopentadienyl zirconiumtriphenyl, and cyclopentadienyl zirconium trineopentyl,cyclopentadienylzirconium trimethyl, cyclopentadienyl-hafnium triphenyl,cyclopentadienylhafniumtrineopentyl, and cyclopentadienylhafniumtrimethyl.

Illustrative, but non-limiting examples of IV and V metallocenes whichcan be usefully employed are monocyclopentadienyl titanocenes such as,pentamethyl-cyclopentadienyl titanium trichloride,pentaethylcyclo-pentadienyl titanium trichloride,bis(pentamethylcyclo-pentadienyl) titanium diphenyl, the carbenerepresented by the formula bis(cyclopentadienyl)titanium=CH₂ andderivatives of this reagent such as bis(cyclopentadienyl)Ti═CH₂.Al(C₃)₃,##STR1## substituted bis(C_(p))Ti(IV) compounds such as bis(indenyl)titanium diphenyl or dichloride, bis(methylcyclopentadienyl)titaniumdiphenyl or dihalides; dialkyl, trialkyl, tetra-alkyl and penta-alkylcyclopentadienyltitanium compounds such asbis(1,2-dimethylcyclopentadienyl)titanium diphenyl or dichloride,bis(1,2-diethylcyclopentadienyl)titanium diphenyl or dichloride andother dihalide complexes; silicon, phosphine, amine or carbon bridgedcyclopentadiene complexes, such as dimethylsilyldicyclopentadienyltitanium diphenyl or dichloride, methyl phosphine dicyclopentadienyltitanium diphenyl or dichloride, methylenedicyclopentadienyl titaniumdiphenyl or dichloride and other complexes described by formulae IV andV.

Illustrative but non-limiting examples of the zirconocenes of Formula IVand V which can be usefully employed are, pentamethylcyclopentadienylzirconium trichloride, pentaethylcyclopentadienyl zirconium trichloride,the alkyl substituted cyclopentadienes, such asbis(ethylcyclopentadienyl)zirconium dimethyl,bis(beta-phenylpropylcyclopentadienyl) zirconium dimethyl,bis(methylcyclopentadienyl) zirconium dimethyl,bis(n-butylcyclopentadienyl) zirconium dimethylbis(cyclohexylmethylcyclopentadienyl)zirconium dimethylbis(n-octyl-cyclopentadienyl)zirconium dimethyl, and haloalkyl anddihydride, and dihalide complexes of the above; dialkyl, trialkyl,tetra-alkyl, and penta-alkyl cyclopentadienes, such asbis(pentamethyl-cyclopentadienyl)zirconium diphenyl,bis(pentamethyl-cyclopentadienyl)zirconium dimethyl,bis(1,2-dimethylcyclopentadienyl)zirconium dimethyl and mono anddihalide and hydride complexes of the above; silicon, phosphorus, andcarbon bridged cyclopentadiene complexes such asdimethylsilyldicyclopentadienyl zirconium dimethyl, methyl halide ordihalide, and methylene dicyclopentadienyl zirconium dimethyl, methylhalide, or dihalide. Mono, di and tri-silyl substituted cyclopentadienylcompounds such as bis(trimethylsilylcyclopentadienyl)zirconiumdichloride and dimethylbis(1,3-di-trimethylsilylcyclo-pentadienyl)zirconium dichloride anddimethyl and bis(1,2,4-tri-trimethylsilylcyclopentadienyl)zirconiumdichloride and dimethyl. Carbenes represented by the formulae C_(p)2Zr═C2 P (C65)2C3, and derivatives of these compounds such as ##STR2##

Mixed cyclopentadienyl metallocene compounds such as cyclopentadienyl(pentamethyl cyclopentadienyl)zirconium dichloride,(1,3-di-trimethylsilylcyclopentadienyl) (pentamethylcyclopentadienyl)zirconium dichloride, and cyclopentadienyl(indenyl) zirconium dichloridecan be employed.

Bis(cyclopentadienyl)hafnium dichloride, bis(cyclopentadienyl)hafniumdimethyl, bis(cyclopentadienyl) vanadium dichloride and the like areillustrative of other metallocenes.

Some preferred metallocenes are bis(cyclo-pentadienyl)zirconiumdimethyl, bis(cyclopenta-dienyl)zirconium dichloride;bis(cyclopentadienyl) titanium dichloride; bis(methylcyclopentadienyl)zirconium dichloride; bis(methylcyclopentadienyl)titanium dichloride;bis(n-butylcyclopentadienyl) zirconium dichloride;dimethylsilyldicyclopentadienyl zirconium dichloride;bis(trimethylsily-cyclopentadienyl)zirconium dichloride; anddimethylsilyldicyclopentadienyl titanium dichloride;bis(indenyl)zirconium dichloride;bis(4,5,6,7-tetrahydroindenyl)zirconium dichloride; the racemic and/ormeso isomer of 1,2-ethylene-bridgedbis(4,5,6,7-tetrahydroindenyl)zirconium dichloride; the racemic and/ormeso isomer of 1,1-dimethylsilyl-bridgedbis(4,5,6,7-tetrahydroindenyl)zirconium dichloride; and the racemicand/or meso isomer of 1,1-dimethylsilyl-bridgedbis(methylcyclopentadienyl)zirconium dichloride.

The alumoxane compounds useful in the polymerization process may becyclic or linear. Cyclic alumoxanes may be represented by the generalformula (R--Al--O)n while linear alumoxanes may be represented by thegeneral formula R(R--Al--O)_(n) 'AlR₂. In the general formula R is a C₁-C₅ alkyl group such as, for example, methyl, ethyl, propyl, butyl andpentyl, n is an integer of from 3 to 20, and n' is an integer from 1 toabout 20. Preferably, R is methyl and n and n' are 4-18. Generally, inthe preparation of alumoxanes from, for example, aluminum trimethyl andwater, a mixture of the linear and cyclic compounds is obtained.

The alumoxane can be prepared in various ways. Preferably, they areprepared by contacting water with a solution of aluminum trialkyl, suchas, for example, aluminum trimethyl, in a suitable organic solvent suchas toluene or an aliphatic hydrocarbon. For example, the aluminum alkylis treated with water in the form of a moist solvent. In an alternativemethod, the aluminum alkyl such as aluminum trimethyl can be desirablycontacted with a hydrated salt such as hydrated copper sulfate orferrous sulfate. Preferably, the alumoxane is prepared in the presenceof a hydrated ferrous sulfate. The method comprises treating a dilutesolution of aluminum trimethyl in, for example, toluene, with ferroussulfate represented by the general formula FeSO₄.7H₂ O. The ratio offerrous sulfate to aluminum trimethyl is desirably about 1 mole offerrous sulfate for 6 to 7 moles of aluminum trimethyl. The reaction isevidenced by the evolution of methane.

The mole ratio of aluminum in the alumoxane to total metal in themetallocenes which can be usefully employed can be in the range of about0.5:1 to 1000:1, and desirably about 1:1 to 100:1. Preferably, the moleratio will be in the range of about 50:1 to 5:1 and most preferablyabout 20:1 to 5:1.

The solvents used in the preparation of the catalyst system are inerthydrocarbons, in particular a hydrocarbon that is inert with respect tothe catalyst system. Such solvents are well known and include, forexample, isobutane, butane, pentane, hexane, heptane, octane,cyclohexane, methylcyclohexane, toluene, xylene and the like.

Polymerization is generally conducted at temperatures ranging betweenabout 20° and 300° C., preferably between about 30° and 200° C. Reactiontime is not critical and may vary from several hours or more to severalminutes or less, depending upon factors such as reaction temperature andthe like. One of ordinary skill in the art may readily obtain theoptimum reaction time for a given set of reaction parameters by routineexperimentation.

The catalyst systems described herein are suitable for thepolymerization of ethylene and 1-butene in solution over a wide range ofpressures. The polymerization can be completed at a pressure of fromabout 10 to 3,000 bar.

After polymerization and, optionally, deactivation of the catalyst(e.g., by conventional techniques such as contacting the polymerizationreaction medium with water or an alcohol, such as methanol, propanol,isopropanol, etc., or cooling or flashing the medium to terminate thepolymerization reaction), the product polymer can be recovered byprocesses well known in the art. Any excess reactants may be flashed offfrom the polymer.

The polymerization may be conducted employing liquid 1-butene as thereaction medium. Alternatively, polymerization may be accomplished inthe presence of a hydrocarbon inert to the polymerization such asbutane, isobutane, pentane, isopentane, hexane, isooctane, decane,toluene, xylene, and the like.

The feedstream containing the 1-butene reactant may optionally containcertain amounts of other C₄ hydrocarbons. More particularly, thefeedstream can comprise less than about 5 weight percent isobutylene, atleast about 12 weight percent total n-butenes (i.e., 1-butene and2-butene), and less than about 1 weight percent butadiene, together withn-butane and isobutane. When used to prepare the EB copolymer, apreferred C₄ feedstream comprises spent C₄ streams produced asby-product in the manufacture of polyisobutylene, wherein the C₄feedstream (often referred to as Raffinate II) contains less than about5 weight percent isobutylene, about 10 to 70 weight percent saturatedbutanes and about 15 to 85 weight percent 1-butene and 2-butene. Thesaturated butanes function as a diluent or solvent in the reactionmixture. Typically the C₄ feedstream is maintained at a sufficientpressure to be in the liquid form both at the reactor inlet and in thereaction mixture itself at the reaction temperature.

The polymers are preferably formed in the substantial absence of addedH₂ gas, that is, the absence of H₂ gas added in amounts effective tosubstantially reduce the polymer molecular weight. More preferably, thepolymerizations will be conducted employing less than 5 wppm, and morepreferably less than 1 wppm, of added H₂ gas, based on the moles of theethylene monomer charged to the polymerization zone.

When carrying out the polymerization in a batch-type fashion, thereaction diluent (if any), ethylene and 1-butene comonomer are chargedat appropriate ratios to a suitable reactor. Care must be taken that allingredients are dry, with the reactants typically being passed throughmolecular sieves or other drying means prior to their introduction intothe reactor. Subsequently, either the catalyst and then the cocatalyst,or first the cocatalyst and then the catalyst are introduced whileagitating the reaction mixture, thereby causing polymerization tocommence. Alternatively, the catalyst and cocatalyst may be premixed ina solvent and then charged to the reactor. As polymer is being formed,additional monomers may be added to the reactor. Upon completion of thereaction, unreacted monomer and solvent are either flashed or distilledoff, if necessary by vacuum, and the low molecular weight copolymerwithdrawn from the reactor.

The polymerization may be conducted in a continuous manner bysimultaneously feeding the reaction diluent (if employed), monomers,catalyst and cocatalyst to a reactor and withdrawing solvent, unreactedmonomer and polymer from the reactor so as to allow a residence time ofingredients long enough for forming polymer of the desired molecularweight and separating the polymer from the reaction mixture.

Employing a metallocene-alumoxane catalyst in accordance with theprocedures and under the conditions as described above can produce anethylene-1-butene copolymer having an ethylvinylidene group terminatingat least about 30% of all polymer chains. However, these proceduresalone do not ensure that the resulting EB copolymer has the requisiteS_(f) value of about zero, the property which determines the polymer tobe suitable for use as a backbone for lubricating oil dispersantadditives.

To produce the EB copolymers of the invention, the following catalysts,procedures and conditions are preferred. The catalyst is preferably acatalyst selected from the general formulae IV and V discussed earlier,wherein s=1, g=1 or 2, and M is a Group 4b transition metal selectedfrom the group consisting of zirconium and titanium, and other valuesand terms as defined earlier. More preferably, the catalyst has thegeneral formula IV, wherein M is zirconium, s=1, g=1, and each R',either the same or different, is an alkyl radical having from 1 to 7carbon atoms or is a hydrocarbyl radical wherein two carbon atoms of theradical are substituted at two adjacent carbon atoms on thecyclopentadienyl ring to form a fused ring structure with thecyclopentadienyl ring selected from the group consisting of indenyl,dihydroindenyl and tetrahydroindenyl, and R" is as defined earlier. Themost preferred catalysts are those of general formula IV with s=1, g=1,and R' as defined in the last sentence, and in which R" is adialkyl-silicon-containing radical bridging the two (C₅ R'_(k)) rings.Illustrative of the most preferred catalysts are1,1-dimethylsilyl-bridged bis(4,5,6,7-tetrahydroindenyl)zirconiumdichloride and 1,1-dimethylsilyl-bridgedbis(methylcyclopentadienyl)zirconium dichloride.

The polymerization is preferably conducted using either liquid 1-buteneor a mixture of liquid 1-butene in an inert hydrocarbon solvent ordiluent at a temperature ranging from about 50° to 200° C. and apressure from about 10 to 100 bar, preferably from about 10 to 30 bar.When a solvent/diluent is employed, it is preferably a C₄ hydrocarbon(i.e., n-butane, isobutane, or mixtures thereof). The 1-butene feed mayalso contain certain amounts of other C₄ hydrocarbons, of the kinds andin the amounts earlier discussed.

The ethylene and 1-butene, whether as a liquid or mixed with asolvent/diluent, may be fed to the reactor as separate streams or as asingle, pre-mixed stream. In either case, the ethylene content of theresulting polymer is controlled in part by the weight percent ethylenecontent, based upon the total weight of monomer, entering the reactor.The EB copolymer typically contains from 1 to about 50 weight percentethylene. Of course, the amount of ethylene incorporated into the EBcopolymer depends upon the particular reaction conditions employed andthe catalyst system selected. For a given set of conditions and a givencatalyst system, the amount of ethylene required to provide an EBcopolymer with a particular ethylene content can be readily determinedby those skilled in the art without undue experimentation.

While conducting the polymerization, there is preferably sufficientmixing of the ethylene and 1-butene monomers in the reactor in order toavoid the production of ethylene homopolymer and to avoid the productionof EB copolymers with S_(f) values greater than zero. More particularly,it is preferred that ethylene monomer and 1-butene monomer togetherenter a turbulent zone inside the reactor. This can be accomplished in astirred reactor, for example, by placing all of the monomer feed inletsnear to each other and near the impeller blade. Mixing is alsofacilitated by the use of a dilute pre-mixed feed as described in theabove referred to Dilute Feed Process patent application.

Sufficient mixing in the reactor promotes the random incorporation ofethylene units in the growing polymer chains, resulting thereby in EBcopolymers of relatively homogeneous composition (both inter-chain andintra-chain) and relatively short sequences of ethylene (i.e., low ESLvalues), compared to analogous EB copolymers produced without suchmixing. As discussed supra, it is believed that the reason the EBpolymers of the invention have S_(f) values of about zero is that thecopolymer molecules contain relatively few crystalline-like, longethylene sequences capable of acting as sites for aggregation.Sufficient mixing, thus, reduces the probability that sites foraggregation will form in the polymer molecules. Effective mixing isespecially important to the production of EB copolymers of the inventionhaving high ethylene content (i.e., above about 35 weight percent),because, without mixing, the resulting EB copolymers would tend to havesufficient ethylenic crystallinity in the copolymer molecules, asmanifested by ESL values above about 2.50, to exhibit S_(f) values abovezero.

With a preferred catalyst employed in accordance with the procedures andconditions as just described an EB copolymer of the invention isproduced; i.e., an EB copolymer which has an S_(f) value of about zeroand an ethylvinylidene group terminating at least about 30% of allpolymer chains.

Functionalized Polymers

The polymers produced in accordance with the present invention can befunctionalized. By functionalized, it is meant that the polymer ischemically modified to have at least one functional group present withinits structure, which functional group is capable of: (1) undergoingfurther chemical reaction (e.g. derivatization) with other materialand/or (b) imparting desirable properties, not otherwise possessed bythe polymer alone, absent such chemical modification.

More specifically, the functional group can be incorporated into thebackbone of the polymer, or as pendant groups from the polymer backbone.

The functional group typically will be polar and contain hetero atomssuch as P, O, S, N, halogen and/or boron. It can be attached to thesaturated hydrocarbon part of the polymer via substitution reactions orto an olefinic portion via addition or cycloaddition reactions.Alternatively, the functional group can be incorporated into the polymerby oxidation or cleavage of a small portion of the end of the polymer(e.g. as in ozonolysis).

Functionalization of the polymer backbone with substituent functionalgroups typically relies on an ethylenic unsaturation, preferably aterminal ethylenic unsaturation, present in the polymer for reactionwith a functional compound containing or constituting the functionalgroup.

Thus, reaction of these functional compounds and the polymer can occurthrough a variety of mechanisms. Useful and preferred functional groupsinclude halogen, carboxyl materials present as acids, esters, salts, oranhydrides, alcohols, amines, ketones, aldehydes and the like.

Useful functionalization reactions include: maleation, which is thereaction of the polymer at the point of unsaturation with maleic acid oranhydride; halogenation of the polymer at the olefinic bond andsubsequent reaction of the halogenated polymer with an ethylenicallyunsaturated functional compound; reaction of the polymer with anunsaturated functional compound by the "ene" reaction absenthalogenation; reaction of the polymer with at least one phenol group;(this permits derivatization in a Mannich Base-type condensation);reaction of the polymer at its point of unsaturation with carbonmonoxide using a Koch-type reaction wherein an acid group such as an isoacid or neo acid is formed; reaction of the polymer with the functionalcompound by free radical addition using a free radical catalyst; andreaction of the polymer by air oxidation methods, epoxidation,chloroamination or ozonolysis.

Characterization of the degree to which the polymer has beenfunctionalized is referred to herein as "functionality".

Functionality refers generally to the average number of functionalgroups present within the polymer structure per polymer chain. Thus,functionality can be expressed as the average number of moles offunctional groups per "mole of polymer". When said "mole of polymer" inthe functionality ratio includes both functionalized andunfunctionalized polymer, functionality is referred to herein as F. Whensaid "mole of polymer" includes only functionalized polymer,functionality is referred to herein as F*.

The distinction between F and F* arises, when all the polymer chains donot undergo reaction with the functional compound. In this instancetypical analytical techniques employed to determine F* will normallynecessitate identification of the weight fraction of functionalizedpolymer, based on the total weight of polymer(functionalized+unfunctionalized) in the sample being analyzed forfunctionality. This weight fraction is commonly referred to as ActiveIngredient or AI. Since the determination of AI is a separate analyticalstep, it can be more convenient to express functionality as F ratherthan F*. In any event, both F and F* are alternate ways ofcharacterizing the functionality.

As a general proposition, the polymer of the present invention can befunctionalized to any functionality effective to impart propertiessuitable for the end use contemplated.

Typically, where the end use of the polymer is for making dispersant,e.g. as derivatized polymer, the polymer will possess dispersant rangemolecular weights (M_(n)) and the functionality will typically besignificantly lower than for polymer intended for making derivatizedmultifunctional V.I. improvers, where the polymer will possess viscositymodifier range molecular weights (M_(n)) as described above.

Moreover, the particular functionality selected, for polymer intended tobe derivatized, will depend on the nature of the derivatizationreactions and type and number of chemical linkages established by thederivatizing compound.

In most instances, one derivatizing linkage will be formed for eachfunctional group, e.g., each carboxy functional group will form 1 esterlinkage. However, certain functional groups can not only actindividually to form a single derivatizing linkage, but alsocollectively such that two functional groups form a single derivatizinglinkage.

For example, where two carboxy groups form an anhydride group and thederivatizing group is a primary amine it is possible to form,inter-alia, two amide linkages or one imide linkage. Thus, while theanhydride group contains two carboxy functional groups, the chemicaleffect obtainable therefrom when both functional groups react, dependson the number of derivatizing linkages achieved.

Accordingly, for purposes of the present invention, when functionalityis reported hereinafter in the context of describing functionalizedpolymer intended for derivatization, and the subject functional groupsare capable of forming less than one derivatizing linkage per functionalgroup, such functionality recitation is to be interpreted asrepresenting the average number of derivatizing linkages to be producedper polymer chain.

Thus, where the derivatizing linkage is to be an imide, and thefunctional groups are anhydride carboxy groups, a functionality of "2"is intended to represent "2" derivatizing imide linkages andconsequently, in effect, an average of two anhydride groups per polymerchain (rather than two carboxy functional groups) since each anhydridewill form one derivatizing imide linkage. However, where thederivatizing linkage is to be an amide, and the functional groups areanhydride carboxy groups, a functionality of "2" represents "2" amidederivatizing linkages and consequently, in effect, a single anhydridegroup since one anhydride will form two amide derivatizing linkages.

Accordingly, while any effective functionality can be imparted to thefunctionalized polymer intended for subsequent derivatization, it iscontemplated that such functionalities, expressed as F*, can be fordispersant end uses, typically not greater than about 3, preferably notgreater than about 2, and typically can range from about 1 to about 3,preferably from about 1.5 to about 2.5, and most preferably from about1.1 to about 2 (e.g. 1.2 to about 1.3).

F and F* values can be interconnected using the AI which for polymers ofthe present invention typically are at least about 0.50, preferably from0.65 to 0.99, more preferably from 0.75 to 0.99, yet more preferably0.85 to 0.99. However, the upper limit of AI is typically from 0.90 to0.99, and more typically 0.90 to 0.95. Where AI is 1.0 F=F*.

Acyl Functionalized Polymer

The most preferred functionalities for technique of the presentinvention is to chemically modify the polymer to have chemical moietiespresent within its structure which contain or constitute at least oneacyl functional group, i.e. ##STR3## wherein X is hydrogen, nitrogen,hydroxy, oxyhydrocarbyl (e.g. ester), oxygen, the salt moiety --OMwherein M is a metal, e.g. alkali, alkaline earth, transition metal,copper zinc and the like, oxyhetero, e.g. --O--Z wherein Z represents ahetero atom such as phosphorus boron, sulfur, which hetero atom may besubstituted with hydrocarbyl or oxyhydrocarbyl groups, or two acylgroups may be joined through (X).

Within this broad class of compounds the most preferred are acyl groupsderived from monounsaturated mono- or dicarboxylic acids and theirderivatives, e.g. esters and salts.

More specifically, polymer functionalized with mono- or dicarboxylicacid material, i.e., acid, anhydride, salt or acid ester suitable foruse in this invention, includes the reaction product of the polymer witha monounsaturated carboxylic reactant comprising at least one memberselected from the group consisting of (i) monounsaturated C₄ to C₁₀dicarboxylic acid (preferably wherein (a) the carboxyl groups arevicinyl, (i.e. located on adjacent carbon atoms) and (b) at least one,preferably both, of said adjacent carbon atoms are part of saidmonounsaturation); (ii) derivatives of (i) such as anhydrides or C₁ toC₅ alcohol derived mono- or diesters of (i); (iii) monounsaturated C₃ toC₁₀ monocarboxylic acid wherein the carbon--carbon double bond isconjugated to the carboxyl group, i.e., of the structure ##STR4## and(iv) derivatives of (iii) such as C₁ to C₅ alcohol derived monoesters of(iii). Upon reaction with the polymer, the double bond of themonounsaturated carboxylic reactant becomes saturated. Thus, forexample, maleic anhydride reacted with the polymer becomes succinicanhydride, and acrylic acid becomes a propionic acid. Reference is madeto EP Publication No. 0,441,548-A1, hereby incorporated by reference.

Suitable unsaturated acid materials thereof which are useful functionalcompounds, include acrylic acid, crotonic acid, methacrylic acid, maleicacid, maleic anhydride, fumaric acid, itaconic acid, itaconic anhydride,citraconic acid, citraconic anhydride, mesaconic acid, glutaconic acid,chloromaleic acid, aconitic acid, crotonic acid, methylcrotonic acid,sorbic acid, 3-hexenoic acid, 10-decenoic acid,2-pentene-1,3,5-tricarboxylic acid, cinnamic acid, and lower alkyl (e.g.C₁ to C₄ alkyl) acid esters of the foregoing, e.g. methyl maleate, ethylfumarate, methyl fumarate, etc. Particularly preferred are theunsaturated dicarboxylic acids and their derivatives, especially maleicacid, fumaric acid and maleic anhydride.

Typically, from about 0.7 to about 4.0 (e.g., 0.8 to 2.6), preferablyfrom about 1.0 to about 2.0, and most preferably from about 1.1 to about1.7 moles of said monounsaturated carboxylic reactant are charged to thereactor per mole of polymer charged.

Normally, not all of the polymer reacts with the monounsaturatedcarboxylic reactant and the reaction mixture will containunfunctionalized polymer. The mono- or dicarboxylic acid functionalizedpolymer, non-functionalized polymer, and any other polymericby-products, e.g. chlorinated polyolefin, (also included within"unfunctionalized" polymer) are collectively referred to herein as"product residue" or "product mixture". The unfunctionalized polymer istypically not removed from the reaction mixture (because such removal isdifficult and would be commercially infeasible) and the product mixture,stripped of any monounsaturated carboxylic reactant can be used infurther derivatization reactions with, for example, amine, alcohol,metal salt and the like as described hereinafter to make dispersant.

The functionality (F) of the polymer can be based upon (i) adetermination of the saponification number (SAP) of the reaction mixtureusing potassium hydroxide and (ii) the number average molecular weightof the polymer charged (M_(n)).

For example, for the case where maleic anhydride is the monounsaturatedcarboxylic reactant, the saponification number (SAP) is the number of mgpure potassium hydroxide which are consumed in the total saponificationof 1 g of material investigated and in the neutralization of any freeacid.

In the hydrolysis and subsequent neutralization of succinic anhydridegroups (SA) two moles of KOH (molecular weight 56.1; two moles=112,200mg) are consumed per mole anhydride groups.

The molecular weight of the polymer (p) is

    M.sub.n (p)+(98* x)

wherein Mn is the number average molecular weight of theunfunctionalized starting polymer charged to the functionalizationreaction mixture, 98 is the molecular weight of maleic anhydride and xis the degree of succination: ##EQU1## Depending on the degree ofsuccination, the consumption of mg KOH per mole of functionalizedpolymer is 2 x mole KOH or

    112200 x

Thus, the saponification number of functionalized polymer is ##EQU2##Therefrom one obtains: ##EQU3## However, since there are two functionalgroups (i.e., carboxyl groups) per succinic group and absentderivatizing linkage considerations, the functionality (F) is determinedfrom the equation: ##EQU4## wherein y is the number 2.

It will be observed that the M_(n) in the formula defining (F) is thenumber average molecular weight of the polymer changed to thefunctionalization reaction mixture. The use of the starting polymer as abasis for determining the M_(n) in the formula (I) is based on theassumptions (1) that the M_(n) of the starting polymer does not undergoa significant change (e.g., not greater than about ±5% change duringfunctionalization and (2) that functionalization does not occurpreferentially within one or more molecular weight regions in thepolymer molecular weight distribution to any significant degree (e.g.,the MWD of the starting polymer is within ±5% of the MWD of only thefunctionalized polymer). Therefore, under these assumptions the M_(n) ofthe starting and functionalized polymer are assumed to be sufficientlysimilar to employ, as a matter of convenience, the M_(n) of the startingpolymer in Formula VI.

To the extent that the above assumptions are incorrect, thefunctionality determined by Formula VI will be incorrect and it will benecessary to determine the M_(n) of functionalized polymer and eitherderive a statistically valid correction factor for the starting polymerM_(n) which reflects the deviations from the above assumptions or employthe functionalized polymer M_(n) directly in Formula VI.

Moreover, as would be obvious to one skilled in the art, when thepolymer is functionalized with a monocarboxylic acid group, y in FormulaVI will be 1.

Alternatively, functionality (F*) for polymer functionalized with maleicanhydride (and absent derivatizing end use considerations) is determinedby the following equation: ##EQU5## wherein AI, SAP and Mn(p) and (y)are as described above.

The polymer of the present invention can be functionalized with themonounsaturated carboxylic reactant by a variety of methods. Suchmethods include halogen assisted "ene" reactions and free radicalgrafting reactions.

Halogen Assisted Polymer Functionalization

For halogen assisted polymer functionalization, the polymer can be firsthalogenated, (e.g. chlorinated or brominated) to about 1 to 8 wt. %,preferably 3 to 7 wt. % chlorine, or bromine, based on the weight ofpolymer, by passing the chlorine or bromine through the polymer at atemperature of 60° C. to 250° C., preferably 110° C. to 160° C., e.g.120° C. to 140° C., for about 0.5 to 10, preferably 1 to 7 hours. Thehalogenated polymer may then be reacted with sufficient monounsaturatedcarboxylic reactant at 100° C. to 250° C., usually about 180° C. to 235°C., for about 0.5 to 10, e.g. 3 to 8 hours, so the product obtained willcontain the desired number of moles of the monounsaturated carboxylicreactant per mole of the halogenated polymer. Processes of this generaltype are taught in U.S. Pat. Nos. 3,087,436; 3,172,892; 3,272,746 andothers. Alternatively, the polymer and the monounsaturated carboxylicreactant are mixed and heated while adding chlorine to the hot material.Processes of this type are disclosed in U.S. Pat. Nos. 3,215,707;3,231,587; 3,912,764; 4,110,349; 4,234,435 and in U.K. 1,440,219.

The polymers of this invention, which are charged to the alkylationreaction zone (zone where the unsaturated acid reacts with polymer), canbe charged alone or together with (e.g., in admixture with) polyalkenes,derived from alkenes having from 1 to 20 carbon atoms (pentene, octene,decene, dodecene, tetradodecene and the like) and homopolymers of C₃ toC₁₀, e.g. C₂ to C₅ monoolefins, and other copolymers of C₂ to C₁₀, e.g.C₂ to C₅ monoolefins, said additional polymer having a number averagemolecular weight of at least about 900, and preferably a molecularweight distribution of less than about 4.0, preferably less than about3.0 (e.g., from 1.2 to 2.8). Preferred such additional olefin polymerscomprise a major molar amount of C₂ to C₁₀, e.g. C₂ to C₅ monoolefin.Such olefins include ethylene, propylene, butylene, isobutylene,pentene, octene-1, styrene, etc. Exemplary of the additionally chargedhomopolymers are polypropylene and polyisobutylene olefins and the likeas well as interpolymers of two or more of such olefins such ascopolymers of: ethylene and propylene (prepared by conventional methods,ethylene-propylene copolymers which are substantially saturated, whereinless than about 10 wt. % of the polymer chains contain ethylenicunsaturation). The additional such olefin polymers charged to thealkylation reaction will usually have number average molecular weightsof at least about 900 and in embodiments for use as dispersants, moregenerally within the range of about 1,300 to about 5,000, more usuallybetween about 1,500 to about 4,000. Particularly useful such additionalolefin polymers have number average molecular weights within the rangeof about 1,500 and about 3,000 with approximately one double bond perchain. A useful additional polymer can be polyisobutylene. Preferred aremixtures of such polyisobutylene with ethylene-propylene copolymerswherein at least 30 wt. % of the copolymer chains contain terminalvinylidene monounsaturation.

The polymer can be heated, preferably with inert gas (e.g., nitrogen)stripping, at elevated temperature under a reduced pressure tovolatilize the low molecular weight polymer components which can then beremoved from the heat treatment vessel. The precise temperature,pressure and time for such heat treatment can vary widely depending onsuch factors as the polymer number average molecular weight, the amountof the low molecular weight fraction to be removed, the particularmonomers employed and other factors. Generally, a temperature of fromabout 60° C. to 100° C. and a pressure of from about 0.1 to 0.9atmospheres and a time of from about 0.5 to 20 hrs. (e.g., 2 to 8 hrs.)will be sufficient.

The polymer and monounsaturated carboxylic reactant and halogen (e.g.,chlorine gas), where employed, are contacted for a time and underconditions effective to form the desired functionalized polymer.Generally, the polymer and monounsaturated carboxylic reactant will becontacted in an unsaturated carboxylic reactant to polymer mole ratiousually from about 0.7:1 to 4:1, and preferably from about 1:1 to 2:1,at an elevated temperature, generally from about 120° C. to 260° C.,preferably from about 160° C. to 240° C. The mole ratio of halogen tomonounsaturated carboxylic reactant charged will also vary and willgenerally range from about 0.5:1 to 4:1, and more typically from about0.7:1 to 2:1 (e.g., from about 0.9 to 1.4:1). The reaction will begenerally carried out, with stirring for a time of from about 1 to 20hrs., preferably from about 2 to 6 hrs.

By the use of halogen, about 65 to 95 wt. % of the polymer will normallyreact with the monounsaturated carboxylic acid reactant. Upon carryingout a thermal reaction without the use of halogen or a catalyst, onlyabout 50 to 75 wt. % of the polymer will react. Chlorination helpsincrease the reactivity.

The reaction is preferably conducted in the substantial absence Of O₂and water (to avoid competing side reactions), and to this end can beconducted in an atmosphere of dry N₂ gas or other gas inert under thereaction conditions. The reactants can be charged separately or togetheras a mixture to the reaction zone, and the reaction can be carried outcontinuously, semi-continuously or batchwise. Although not generallynecessary, the reaction can be carried out in the presence of a liquiddiluent or solvent, e.g., a hydrocarbon diluent such as minerallubricating oil, toluene, xylene, dichlorobenzene and the like. Thefunctionalized polymer thus formed can be recovered from the liquidreaction mixture, e.g., after stripping the reaction mixture, ifdesired, with an inert gas such as N₂ to remove unreacted unsaturatedcarboxylic reactant.

If desired, a catalyst or promoter for reaction of the olefinic polymerand monounsaturated carboxylic reactant (whether the olefin polymer andmonounsaturated carboxylic reactant are contacted in the presence orabsence of halogen (e.g., chlorine)) can be employed in the reactionzone. Such catalyst of promoters include alkoxides of Ti, Zr, V and Al,and nickel salts (e.g., Ni acetoacetonate and Ni iodide) which catalystsor promoters will be generally employed in an amount of from about 1 to5,000 ppm by weight, based on the mass of the reaction medium.

"ENE" Acid Functionalized Polymer

The polymer and the aforedescribed monounsaturated carboxylic reactantcan be contacted at elevated temperature to cause a thermal "ene"reaction to take place. Thermal "ene" reactions have been heretoforedescribed in U.S. Pat. Nos. 3,361,673 and 3,401,118, the disclosures ofwhich are hereby incorporated by reference in their entirety.

Functionalized polymer can be prepared using a thermal "ene" typereactor or by chlorination as disclosed in EP Application No. 91300843.9(=Published Application No. 441,548), hereby incorporated by reference.

Free Radical Grafted Acid Functionalized

An ethylenically unsaturated carboxylic acid or derivative thereof maybe grafted onto saturated or unsaturated polymer backbone in solution orin solid form using a radical initiator. It is carried out at anelevated temperature in the range of about 100° C. to 250° C.,preferably 120° C. to 190° C. and more preferably at 150° C. to 180° C.Suitable unsaturated acids include those described above.

The free radical initiators which may be used are peroxides,hydroperoxides, and azo compounds and preferably those which have aboiling point greater than about 100° C. and decompose thermally withinthe grafting temperature range to provide free radicals. Representativeof these free radical initiators are azobutyronitrile and2,5-dimethyl-hex-3-yne-2,5 bis-tertiary-butyl peroxide. The initiator isused in an amount of between about 0.005% and about 1% by weight basedon the weight of the reaction mixture. The grafting is preferablycarried out in an inert atmosphere, such as under nitrogen blanketing.The resulting functionalized polymer is characterized by havingcarboxylic acid moieties or derivatives randomly distributed within itsstructure.

Free radical grafting is particularly suited for functionalizingintermediate molecular weight polymers pursuant to preparingmultifunctional viscosity index improvers, wherein mechanical or thermalshearing techniques (e.g., mastication) are often employed. Thisfunctionalization technique nonetheless can be employed to functionalizepolymer intended to make dispersants, but the functionality typicallywill be limited, and/or derivatization and/or post-treatment istypically controlled to avoid gellation of the dispersant as describedin commonly assigned U.S. Ser. No. 992,516 filed Dec. 17, 1992 (DocketNo. PT-964), titled Gel Free Ethylene Interpolymer Derived DispersantAdditive Useful in Oleaginous Compositions, and U.S. Ser. No. 991,837filed Dec. 17, 1992 titled Gel-Free (α-Olefin Derived DispersantAdditive Useful in Oleaginous Compositions (Docket No. PT-967) thedisclosure of which are herein incorporated by reference.

Hydroxy Aromatic Compounds

A further suitable functionalization technique involves the reaction ofhydroxy aromatic functional compounds with the polymer.

Hydroxy aromatic compounds useful in the preparation of thefunctionalized polymer of this invention include those compounds havingthe formula:

    H--Ar--(OH).sub.c

wherein Ar represents ##STR5## wherein a is 1 or 2, R" is a halogenradical such as the bromide or chloride radical, b is an integer from 0to 2, and c is an integer from 1 to 2. Illustrative of such Ar groupsare phenylene, biphenylene, naphthylene and the like.

The polymer, i.e. EB copolymer, having at least one olefinicunsaturation and hydroxy aromatic compound is contacted in the presenceof a catalytically effective amount of at least one acidic alkylationcatalyst under conditions effective to alkylate the aromatic group ofthe hydroxy aromatic compound. The alkylation catalyst is conventionaland can, with the polymer, comprise inorganic acids such as H₃ PO₄, H₂SO₄, HF, BF₃, HF--BF₃ and the like. The acid catalyst can also comprisean acidic ion exchange resin having acidic groups adsorbed or absorbedthereon, such as Amberlyst 15 resin (Rohm & Haas Co.), and the like.Also useful as catalysts are preformed complexes (or complexes formed insitu) of the foregoing with C₂ to C₁₀ ethers, C₁ to C₁₀ alcohols, C₂ toC₁₀ ketones, phenols and the like, such as BF₃ complexed with dimethylether, diethyl ether, phenol, and the like.

The hydroxy aromatic compound and polymer will be generally contacted ina ratio of from about 0.1 to 10, preferably from about 1 to 7, morepreferably from about 2 to 5 moles of the aromatic compound per mole ofthe polymer. The selected acid catalyst can be employed in widelyvarying concentrations. Generally, when the acid catalyst comprises aninorganic catalyst, the acid catalyst will be charged to provide atleast about 0.001, preferably from about 0.01 to 0.5, more preferablyfrom about 0.1 to 0.3 moles of catalyst per mole of hydroxy aromaticcompound charged to the alkylation reaction zone. Use of greater than 1mole of the inorganic catalyst per mole of hydroxy aromatic compound isnot generally required. When the acid catalyst comprises a supportedcatalyst, such as an acidic ion exchange resin, the reactants can becontacted with the ion exchange resin employing any conventionalsolid-liquid contacting techniques, such as by passing the reactantsthrough the resin (e.g., in a catalyst bed or through a membraneimpregnated or otherwise containing the resin catalyst) and the upperlimit on the moles of catalyst employed per mole of hydroxy aromaticcompound is not critical.

The temperature for alkylation can also vary widely, and will usuallyrange from about 20° C. to 250° C., preferably from about 30° C. to 150°C., more preferably from about 50° C. to 80° C.

The alkylation reaction time can vary and will generally be from about 1to 5 hrs., although longer or shorter times can also be employed. Thealkylation process can be practiced in a batchwise, continuous orsemicontinuous manner. Preferably, the acid catalyst is neutralizedand/or removed prior to contacting the alkylation product mixture with anucleophilic reagent (e.g., polyamine) and aldehyde reactant. Theneutralization can be accomplished by contacting the crude alkylationproduct with gaseous ammonia or other basically reacting compound (e.g.,aqueous NaOH, KOH, and the like), followed by filtration to remove anyprecipitated neutralized catalyst solids. Alkylation processes of theabove types are known and are described, for example, in U.S. Pat. Nos.3,539,633 and 3,649,229, the disclosures of which are herebyincorporated by reference. Oxidation Oxidation of the polymer representsanother suitable technique applicable to the polymers of the presentinvention. This technique can be further categorized as including airoxidation (e.g. oxidation with oxygen or oxygen-containing gas),ozonolysis, and hydroperoxidation.

As a result of oxidation, the ethylene and butene units at the terminaland intermediate of the polymer chain are randomly oxidized and thushave at least one oxygen containing functional group.

Examples of the oxygen containing functional group include carboxyl,oxycarboxyl (ester bond), formyl, carbonyl and hydroxyl groups. Thefunctionality (F*) of the oxidized polymer will be as describedgenerally hereinabove.

More specifically, the polymer of the present invention havingunsaturation, typically terminal unsaturation, can be functionalized byan air oxidation process such as those recited in U.S. Pat. Nos.4,925,579 and 4,943,658, both hereby incorporated by reference.

A useful process comprises contacting the polymer, preferably in theliquid state, with molecular oxygen, ozone or a mixture thereof at atemperature of from 100° C. to 250° C., typically from 120° C. to 190°C. to oxidize the polymer until an oxygen content in the range of from0.1 to 20% by weight is reached or until an acid value having a range offrom 0.1 to 50 or saponification value in the range of 0.1 to 100 arereached. Pressures are typically up to 600 bar, and preferably 50 to 300bar. The polymer oxidized at this extent is effective in formulatingdispersants and viscosity modifiers.

The oxidatively modified polymer of the present invention can beprepared by oxidizing the above recited polymers with a gas containingmolecular oxygen and/or ozone, optionally in an inert hydrocarbonmedium. The molecular oxygen-containing gas used for oxidation includesoxygen gas, air and gaseous mixtures of molecular oxygen diluted with aninert gas such as nitrogen, argon and carbon dioxide to a properconcentration. The ozone-containing gases include ozone, gaseousmixtures of ozone and oxygen or air, and gaseous mixtures of ozone orozone plus oxygen or air diluted with an inert gas such as nitrogen,argon and carbon dioxide to a proper concentration. The gas containingmolecular oxygen and ozone may be any mixtures of the foregoing.

The inert hydrocarbon medium which may be used in oxidative reactioninclude, for example, pentane, hexane, heptane, octane, decane,dodecane, kerosine, gas oil, benzene, toluene, xylene and the like.

Oxidation of the polymer is generally carried out in the absence of acatalyst, but may be carried out in the presence of a radical initiatoror an oxidative catalyst. Examples of the radical initiator includeorganic peroxides such as benzoyl peroxide, di-tert-butyl peroxide,tert-butyl hydroperoxide, dicumyl peroxide, and2,5-dimethyl-2,5-di(peroxybenzoate)-hexyne-3. Examples of the oxidativecatalyst include inorganic compounds such as cobalt acetate, manganesechloride, copper, nickel oxide, manganese dioxide, and cobaltnaphthenate.

Oxidation of the polymer is effected at a temperature in the range offrom 100° C. to 250° C., preferably from 120° C. to 230° C., morepreferably from 130° C. to 200° C. The time taken for the oxidationreaction ranges from 10 minutes to 20 hours, preferably from 30 minutesto 10 hours. The oxidation may be carried out either in atmosphericpressure or in applied pressure. The reaction mixture obtained at theend of oxidative reaction may be worked up by a conventional techniqueobtaining the oxidatively modified copolymer of the present invention.

U.S. Pat. No. 4,076,738; EP Publication No. 0389722 and WO90/09371relate to ozonolysis. A useful method of ozonolysis is to introduce astream comprising one to 10% by weight of ozone in a carrier gas. Theozone concentration in the gas is not critical and any practicalconcentration can be used. The carrier gas can be nitrogen, air oroxygen and is preferably air or oxygen. Useful ozonation temperaturesare from about -80° C. to 60° C. and preferably -10° C. to 30° C.

The polymer of the present invention, can also be functionalized byhydroperoxidation in accordance with the method of U.S. Pat. No.4,925,579. Hydroperoxidation can be carried out in solvents relativelyinert to the reaction conditions. Solvents such as toluene, xylene, ormineral neutral oils can be used. Preferred solvents are benzene,chlorobenzene, t-butyl-benzene and the like. Free radical initiators areused which can be peroxides, hydroperoxides and azo compounds, which maybe used alone or as mixtures thereof, include, for example, cumenehydroperoxide, dicumyl peroxide, benzoyl peroxide,azo-bis(isobutyronitrile), tertiary butyl hydroperoxide, and the like.Preferably, the free radical initiator is cumene hydroperoxide, dicumylperoxide, and mixtures thereof These free radical initiators have beenconventionally employed in effecting hydroperoxidation of polymers andcopolymers.

The more vigorous the oxidation conditions and the longer the length oftime maintaining such conditions, the greater the number of carboxylgroups introduced into the starting material. It is sufficient, however,that on an average at least one carboxyl is introduced into eachmolecule of the starting material.

The product produced by the hydroperoxidation reaction is an oil-solubleproduct of lower molecular weight than the starting material. Themolecular weight depends upon the extent and conditions employed duringthe oxidation reaction. Ultimately, the intermediate hydroperoxidizedpolymers are converted by further oxidation reactions to fragmented ordegraded polymer materials having a viscosity average molecular weightof from about one-half to about one-tenth of the molecular weight of theoriginal material. The functionality (F*) of the carboxylated polymersis in the range of from 1 to 15 as generally described above dependingon the end use.

Hydroformylation

The polymer of the present invention can be functionalized byhydroformylation by methods of the type disclosed in U.S. Pat. Nos.4,832,702; 4,859,210 and GB Patent No. 1,049,291, all herebyincorporated by reference.

The process of hydroformylation can be carried out using a conventionalrhodium or cobalt catalyst at from 80° C. to 200° C., preferably 120° C.to 190° C. and under a CO/H₂ pressure of up to 600, preferably 50 to 300bar. The reaction can be conducted in two stages. The first stage isconducted at a low temperature, e.g., 100° C. to 150° C., and the secondstage at a high temperature, e.g., 160° C. to 200° C. Theoxygen-containing polymer resulting from the hydroformylation processare formed by addition of carbon monoxide and hydrogen to a double bond.Reactive double bonds are predominantly converted to aldehydes andketones. Isomerization can cause a mixture of aldehydes to be obtained.

Epoxidation

The polymers of the present invention can be functionalized byepoxidation as disclosed in U.S. Pat. No. 4,981,605, JapaneseApplication JP H01-132,605, PCT WO90/10022 and EP 461,744, all herebyincorporated by reference.

In accordance with the method disclosed in Japanese ApplicationS62-289292 (=Published Application No. H01-132,605), hydrogen peroxideor organic peroxides are allowed to react with the polymer. Inparticular, the polymer is mixed with an acid, preferably an organicacid, such as formic or acetic acid plus hydrogen peroxide. It ispreferred that a buffer in the form of sodium hydrogen phosphate, sodiumcarbonate or sodium bicarbonate be present. The amount of organic acidper mole of hydrogen peroxide is typically from 2 to 50 moles andpreferably 5 to 25 moles. The reaction temperature is typically from 0°C. to 60° C. and preferably 10° C. to 50° C., the reaction time oftypically from 0.5 to 20 hours, preferably 1 to 10 hours. The amount ofhydrogen peroxide added typically will be 1 to 10, preferably 2 to 5moles per mole of unsaturated bond of polymer, and the amount of addedorganic acid typically will be 10 to 100, and preferably 20 to 50 moles.The amount of buffer per mole of organic acid typically will be 0.05 to0.5, preferably 0.1 to 0.3 moles. The reaction temperature typicallywill be 0° C. to 100° C., preferably 20° C. to 80° C., and the timerequired typically will be 1 to 30 and preferably to 20 hrs. The polymerconcentration typically will be 5 to 400, preferably 10 to 300 g perliter.

Where an organic peroxide is used it typically will be from 1 to 10,preferably 1 to 5 moles per mole of unsaturated bond of the polymer. Thecompound of preference is organic per carbonate. The reactiontemperature typically will be 0° C. to 100° C., preferably 10° C. to 80°C. and the reaction time typically will be 0.1 to 10, preferably 0.5 to5 hours. The polymer concentration should be 5 to 400 g per liter andpreferably 10 to 300 g per liter.

The solvent used in the preparation of liquid epoxidated EB copolymercan be an aromatic hydrocarbon such as benzene, toluene or xylene or anether such as ethyl ether, tetrahydrofuran or dioxane. This method isalso disclosed in U.S. Pat. No. 4,981,605.

The functionalized polymer produced by epoxidation contains epoxy groupsformed at the carbon-carbon unsaturation bond. Preferably the polymer isterminally unsaturated.

Koch Functionalized Polymer

Yet another method to functionalize the polymer of the present inventionis by a Koch-type reaction as disclosed in commonly assigned copendingU.S. Ser. No. 992,403, filed Dec. 18, 1992 (Docket No. PT-941), andentitled Functionalization of Polymers Based on Koch Chemistry andDerivatives Thereof, herein incorporated by reference.

The polymer of the present invention having unsaturation, preferablyterminal unsaturation, can be reacted via the Koch mechanism to befunctionalized with an acid or an ester. The polymer is contacted withcarbon monoxide or a suitable carbon monoxide source such as carbonmonoxide gas or formic acid, in the presence of an acidic catalyst. Thecatalyst preferably has a Hammett Scale Value acidity (Ho) of less than-7 in order to be sufficiently active, particularly to form neostructures. Preferably the Hammett acidity of the catalyst is in therange of from -8 to -11.5. Useful catalysts include H₂ SO₄, BF₃, and HF.The catalyst causes a carbenium ion to form at the point ofunsaturation. The carbon monoxide reacts with the carbenium ion formingan acylium ion. Water or a hydroxy-containing compound or a thiolcontaining compound can be added to react with the acylium cation toform a carboxylic acid or a carboxylic ester/or a thiol ester.Preferably, the hydroxy-containing compound or water is added incombination with the catalyst as a catalyst complex. Preferred catalystcomplexes include (BF₃.H₂ O) and (BF₃. substituted phenols) with a mostpreferred catalyst complex being BF₃.2,4 dichlorophenyl.

In accordance with the Koch process carboxyl groups, includingcarboxylic acid or carboxylic esters, can be formed at moderatetemperatures and pressures at the point of unsaturation of the polymerof the present invention. The polymer is heated to a desired temperaturerange which is typically between -20° C. to 200° C. and preferably from0° C. to 80° C. The pressure in the reactor can be maintained based onthe carbon monoxide source, with pressures ranging up to 5,000 psig witha preferred range of from 500 to 3,000 psig.

Other functionalized polymers include those suitable for use asintermediates in making ash-producing detergents as describedhereinbelow including sulfurized alkylphenols, alkyl sulfonic acids,alkyl salicylates, alkyl naphthanates wherein the alkyl group is derivedfrom the polymer of the present invention.

The functionalized polymers of the present invention may be used as anadditive agent for oleaginous compositions such as fuels and lubricatingoils as discussed hereinafter.

Derivatized Polymers

As indicated above, a functionalized polymer is one which is chemicallymodified primarily to enhance its ability to participate in a widervariety of chemical reactions than would otherwise be possible with theunfunctionalized polymer.

In contrast, a derivatized polymer is one which has been chemicallymodified to perform one or more functions in a significantly improvedway relative to the unfunctionalized polymer and/or the functionalizedpolymer. Representative of such functions, are dispersancy and/orviscosity modification in lubricating oil compositions.

Typically, derivatization is achieved by chemical modification of thefunctionalized polymer.

More specifically, the functionalized polymer can be derivatized byreaction with at least one derivatizing compound to form derivatizedpolymers. The derivatizing compound typically contains at least onereactive derivatizing group. The reactive derivatizing group istypically selected to render it capable of reacting with the functionalgroups of the functionalized polymers by the various reactions describedbelow. Representative of such reactions are nucleophilic substitution,Mannich Base condensation, transesterification, salt formations, and thelike. The derivatizing compound preferably also contains at least oneadditional group suitable for imparting the desired properties to thederivatized polymer, e.g., polar groups. Thus, such derivatizingcompounds typically will contain one or more groups including amine,hydroxy, ester, amide, imide, thio, thioamido, oxazoline or salt groupsderived from reactive metal or reactive metal compounds.

Thus, the derivatized polymers can include the reaction product of theabove recited functionalized polymer with a nucleophilic reactant whichinclude amines, alcohols, amino-alcohols and mixtures thereof to formoil soluble salts, amides, imides, oxazoline, reactive metal compoundsand esters of mono- and dicarboxylic acids, esters or anhydrides.

Suitable properties sought to be imparted to the derivatized polymerinclude especially dispersancy, but also multifunctional viscositymodification, antioxidancy, friction modification, antiwear, antirust,seal swell, and the like.

Ash-Producing Dispersants

The ash-producing detergents which can be made using the functionalizedpolymers of the present invention are exemplified by oil-soluble neutraland basic salts of alkali or alkaline earth metals with alkyl phenols,alkyl sulfonic acids, carboxylic acids, or organic phosphorus acidscharacterized by at least one direct carbon-to-phosphorus linkage suchas those prepared from the functionalized olefin polymer of the presentinvention (e.g., functionalized polymer having a molecular weight of1,500) with a phosphorizing agent such as phosphorus trichloride,phosphorus heptasulfide, phosphorus pentasulfide, phosphorus trichlorideand sulfur, white phosphorus and a sulfur halide, or phosphorothioicchloride. The most commonly used salts of such acids are those ofsodium, potassium, lithium, calcium, magnesium, strontium and barium.The alkyl groups of the above acids or compounds constitute the polymerof the present invention.

The term "basic salt" is used to designate metal salts wherein the metalis present in stoichiometrically larger amounts than the derivatizedpolymer. The commonly employed methods for preparing the basic saltsinvolve heating a mineral oil solution of the acid with a stoichiometricexcess of a metal neutralizing agent such as metal oxide, hydroxide,carbonate, bicarbonate, or sulfide at a temperature of about 50° C. andfiltering the resulting mass. The use of a "promoter" in theneutralization step to aid the incorporation of a large excess of metallikewise is known. Examples of compounds useful as the promoter includephenolic substance such as phenol, napthol, alkylphenol, thiophenol,sulfurized alkylphenol, and condensation products of formaldehyde with aphenolic substance; alcohols such as methanol, 2-propanol, octylalcohol, cellosolve, ethylene glycol, stearyl alcohol, and cyclohexylalcohol; and amines such as aniline, phenylenediamine,phenyl-beta-napthylamine, and dodecylamine. A particularly effectivemethod for preparing the basic salts comprises mixing an acid with anexcess of a basic alkaline earth metal neutralizing agent and at leastone alcohol promoter, and carbonating the mixture at an elevatedtemperature such as 60° C. to 200° C. This class of materials isdiscussed further hereinbelow in connection with detergents and metalrust inhibitors.

Preferred ash-producing detergents which can be derived from thefunctionalized polymers of the present invention include the metal saltsof alkyl sulfonic acids, alkyl phenols, sulfurized alkyl phenols, alkylsalicylates, alkyl naphthenates and other oil soluble mono- anddicarboxylic acids. Highly basic (viz, overbased) metal salts, such ashighly basic alkaline earth metal alkyl sulfonates (especially Ca and Mgsalts) are frequently used as detergents. They are usually produced byheating a mixture comprising an oil-soluble alkyl sulfonate or alkarylsulfonic acid, with an excess of alkaline earth metal compound abovethat required for complete neutralization of any sulfonic acid present,and thereafter forming a dispersed carbonate complex by reacting theexcess metal with carbon dioxide to provide the desired overbasing. Thesulfonic acids are typically obtained by the sulfonation of alkylsubstituted aromatic hydrocarbons such as those obtained from thefractionation of petroleum by distillation and/or extraction or by thealkylation of aromatic hydrocarbons as for example those obtained byalkylating benzene, toluene, xylene, naphthalene, diphenyl and thehalogen derivatives such as chlorobenzene, chlorotoluene andchloronaphthalene. The alkylation with the polymers of the presentinvention may be carried out in the presence of a catalyst, the polymeralkylating agents.

The alkaline earth metal compounds which may be used in neutralizingthese acids to provide the compounding metal salts include the oxidesand hydroxides, alkoxides, carbonates, carboxylate, sulfide,hydrosulfide, nitrate, borates and ethers of magnesium, calcium, andbarium. Examples are calcium oxide, calcium hydroxide, magnesium acetateand magnesium borate. As noted, the alkaline earth metal compound isused in excess of that required to complete neutralization of thealkaryl sulfonic acids. Generally, the amount ranges from about 100 toabout 220%, although it is preferred to use at least 125% of thestoichiometric amount of metal required for complete neutralization.

Various other preparations of basic alkaline earth metal sulfonates areknown, such as those described in U.S. Pat. Nos. 3,150,088 and3,150,089, wherein overbasing is accomplished by hydrolysis of analkoxide-carbonate complex with the alkaryl sulfonate in a hydrocarbonsolvent/diluent oil.

Ashless Dispersants

The derivatized polymer compositions of the present invention, can beused as ashless dispersants in lubricant and fuel compositions. Ashlessdispersants are referred to as being ashless despite the fact that,depending on their constitution, the dispersants may, upon combustion,yield a non-volatile material such as boric oxide or phosphoruspentoxide. The compounds useful as ashless dispersants generally arecharacterized by a "polar" group attached to a relatively high molecularweight hydrocarbon chain supplied by the polymer of the presentinvention. The "polar" group generally contains one or more of theelements nitrogen, oxygen and phosphorus. The solubilizing chains aregenerally higher in molecular weight than those employed with themetallic based dispersants, but in some instances they may be quitesimilar.

Various types of ashless dispersants can be made by derivatizing thepolymer of the present invention and are suitable for use in thelubricant compositions. The following are illustrative:

1. Reaction products of functionalized polymer of the present inventionderivatized with nucleophilic reagents such as amine compounds, e.g.nitrogen-containing compounds, organic hydroxy compounds such as phenolsand alcohols, and/or basic inorganic materials.

More specifically, nitrogen- or ester-containing ashless dispersantscomprise members selected from the group consisting of oil-solublesalts, amides, imides, oxazolines and esters, or mixtures thereof, ofthe polymer of the present invention, functionalized with mono- anddicarboxylic acids or anhydride or ester derivatives thereof, saidpolymer having dispersant range molecular weights as definedhereinabove.

At least one functionalized polymer is mixed with at least one of amine,alcohol, including polyol, aminoalcohol, etc., to form the dispersantadditives. One class of particularly preferred dispersants includesthose derived from the polymer of the present invention functionalizedmono- or dicarboxylic acid material, e.g. succinic anhydride, andreacted with (i) a hydroxy compound, e.g. pentaerythritol, (ii) apolyoxyalkylene polyamine, e.g. polyoxypropylene diamine, and/or (iii) apolyalkylene polyamine, e.g., polyethylene diamine or tetraethylenepentamine referred to herein as TEPA. Another preferred dispersant classincludes those derived from functionalized polymer reacted with (i) apolyalkylene polyamine, e.g. tetraethylene pentamine, and/or (ii) apolyhydric alcohol or polyhydroxy-substituted aliphatic primary amine,e.g., pentaerythritol or trismethylolaminomethane.

2. Reaction products of the polymer of the present inventionfunctionalized with an aromatic hydroxy group and derivatized withaldehydes (especially formaldehyde) and amines (especially polyalkylenepolyamines), through the Mannich reaction, which may be characterized as"Mannich dispersants".

3. Reaction products of the polymer of the present invention which havebeen functionalized by reaction with halogen and then derivatized byreaction with amines (e.g. direct amination), preferably polyalkylenepolyamines. These may be characterized as "amine dispersants" andexamples thereof are described, for example, in U.S. Pat. Nos.3,275,554; 3,438,757; 3,454,555; 3,565,804; 3,755,433; 3,822,209 and5,084,197, the disclosures of which are herein incorporated byreference.

Derivatized Polymer From Amine Compounds

Useful amine compounds for derivatizing functionalized polymers compriseat least one amine and can comprise one or more additional amines orother reactive or polar groups. Where the functional group is acarboxylic acid, ester or derivative thereof, it reacts with the amineto form an amide. Where the functional group is an epoxy it reacts withthe amine to form an amino alcohol. Where the functional group is ahalide the amine reacts to displace the halide. Where the functionalgroup is a carbonyl group it reacts with the amine to form an imine.

Amine compounds useful as nucleophilic reactants for reaction with thefunctionalized polymer of the present invention include those disclosedin U.S. Pat. Nos. 3,445,441, 5,017,299 and 5,102,566, all herebyincorporated by reference. Preferred amine compounds include mono- and(preferably) polyamines, of about 2 to 60, preferably 2 to 40 (e.g. 3 to20), total carbon atoms of about 1 to 12, preferably 3 to 12, and mostpreferably 3 to 9 nitrogen atoms in the molecule. These amines may behydrocarbyl amines or may be hydrocarbyl amines including other groups,e.g., hydroxy groups, alkoxy groups, amide groups, nitriles, imidazolinegroups, and the like. Hydroxy amines with 1 to 6 hydroxy groups,preferably 1 to 3 hydroxy groups, are particularly useful. Preferredamines are aliphatic saturated amines, including those of the generalformulas: ##STR6## wherein R⁵, R⁶, R⁷ and R⁸ are independently selectedfrom the group consisting of hydrogen; C₁ to C₂₅ straight or branchedchain alkyl radicals; C₁ to C₁₂ alkoxy; C₂ to C₆ alkylene radicals; C₂to C₁₂ hydroxy amino alkylene radicals; and C₁ to C₁₂ alkylamino C₂ toC₆ alkylene radicals; and wherein R⁸ can additionally comprise a moietyof the formula: ##STR7## wherein R⁶ is as defined above, and wherein rand r' can be the same or a different number of from 2 to 6, preferably2 to 4; and t and t' can be the same or different and are numbers offrom 0 to 10, preferably 2 to 7, and most preferably about 3 to 7.Preferably that the sum of t and t' is not greater than 15. To assure afacile reaction, it is preferred that R⁵, R⁶, R⁷, R⁸, r, r', t and t' beselected in a manner sufficient to provide the compounds of Formulae(VII) and (VIII) with typically at least 1 primary or secondary aminegroup, preferably at least 2 primary or secondary amine groups. This canbe achieved by selecting at least 1 of said R⁵, R⁶, R⁷ and R⁸ groups tobe hydrogen or by letting t in Formula 6 be at least 1 when R⁸ is H orwhen the Formula (IX) moiety possesses a secondary amino group. The mostpreferred amine of the above formulas are represented by Formula (VIII)and contain at least 2 primary amine groups and at least 1, andpreferably at least 3, secondary amine groups.

Non-limiting examples of suitable amine compounds include:1,2-diaminoethane; 1,3-diaminopropane; 1,4-diaminobutane;1,6-diaminohexane; polyethylene amines such as diethylene triamine;triethylene tetramine; tetraethylene pentamine; polypropylene aminessuch as 1,2-propylene diamine; di-(1,2-propylene)triamine;di-(1,3-propylene)triamine; N,N-dimethyl-1,3-diaminopropane;N,N-di-(2-aminoethyl) ethylene diamine;N,N-di-(2-hydroxyethyl)-1,3-propylene diamine; 3-dodecyloxypropylamine;N-dodecyl-1,3-propane diamine; tris hydroxymethylaminomethane (THAM);diisopropanol amine; diethanol amine; triethanol amine; mono-, di-, andtri-tallow amines; amino morpholines such asN-(3-aminopropyl)morpholine; and mixtures thereof. Monoamines includemethyl ethyl amine, methyl octadecyl amines, anilines, diethylol amine,dipropyl amine, etc.

Other useful amine compounds include: alicyclic diamines such as1,4-di(aminomethyl) cyclohexane, and heterocyclic nitrogen compoundssuch as imidazolines, and N-aminoalkyl piperazines of the generalformula (X): ##STR8## wherein p₁ and p₂ are the same or different andare each integers of from 1 to 4, and n₁, n₂ and n₃ are the same ordifferent and are each integers of from 1 to 3. Non-limiting examples ofsuch amines include 2-pentadecyl imidazoline; N-(2-aminoethyl)piperazine; etc.

Commercial mixtures of amine compounds may advantageously be used. Forexample, one process for preparing alkylene amines involves the reactionof an alkylene dihalide (such as ethylene dichloride or propylenedichloride) with ammonia, which results in a complex mixture of alkyleneamines wherein pairs of nitrogens are joined by alkylene groups, formingsuch compounds as diethylene triamine, triethylenetetramine,tetraethylene pentamine and isomeric piperazines. Low costpoly(ethyleneamine) compounds averaging about 5 to 7 nitrogen atoms permolecule are available commercially under trade names such as "PolyamineH", "Polyamine 400", "Dow Polyamine E-100", etc.

Useful amines also include polyoxyalkylene polyamines such as those ofthe formula:

    NH.sub.2 --alkylene--(--O--alkylene--).sub.m --NH.sub.2    (XI)

where m has a value of about 3 to 70 and preferably 10 to 35; and theformula:

    R.sup.9 --(--alkylene--(--O--alkylene--).sub.n --NH.sub.2).sub.a(XII)

where n has a value of about 1 to 40 with the provision that the sum ofall the n values is from about 3 to about 70 and preferably from about 6to about 35, and R⁹ is a polyvalent saturated hydrocarbon radical of upto 10 carbon atoms wherein the number of substituents on the R⁹ group isrepresented by the value of "a", which is a number of from 3 to 6. Thealkylene groups in either formula (XI) or (XII) may be straight orbranched chains containing about 2 to 7, and preferably about 2 to 4carbon atoms.

The polyoxyalkylene polyamines of formulas (XI) or (XII) above,preferably polyoxyalkylene diamines and polyoxyalkylene triamines, mayhave average molecular weights ranging from about 200 to about 4,000 andpreferably from about 400 to about 2,000. The preferred polyoxyalkylenepolyamines include the polyoxyethylene and polyoxypropylene diamines andthe polyoxypropylene triamines having average molecular weights rangingfrom about 200 to 2,000. The polyoxyalkylene polyamines are commerciallyavailable and may be obtained, for example, from the Jefferson ChemicalCompany, Inc. under the trade name "Jeffamines D-230, D-400, D-1000,D-2000, T-403, etc.

Other suitable amines include the bis(para-amino cyclohexyl) methaneoligomers disclosed in U.S. Ser. No. 547,930, filed Jul. 3, 1990, thedisclosure of which is herein incorporated by reference.

A particularly useful class of amines are the polyamido and relatedamines disclosed in U.S. Pat. Nos. 4,857,217; 4,963,275 and 4,956,107,the disclosures of which are herein incorporated by reference, whichcomprise reaction products of a polyamine and an alpha, beta unsaturatedcompound of the formula: ##STR9## wherein X is sulfur or oxygen, Y is--OR¹³, SR¹³, or --NR¹³ (R¹⁴), and R¹⁰, R¹¹, R¹², R¹³ and R¹⁴ are thesame or different and are hydrogen or substituted or unsubstitutedhydrocarbyl. Any polyamine, whether aliphatic, cycloaliphatic, aromatic,heterocyclic, etc., can be employed provided it is capable of addingacross the acrylic double bond and amidifying with, for example, thecarbonyl group (--C(O)--) of the acrylate-type compound of formula(XIII), or with the thiocarbonyl group (--C(S)--) of thethioacrylate-type compound of formula (XIII).

When R¹⁰, R¹¹, R¹², R¹³ or R¹⁴ in Formula (XIII) are hydrocarbyl, thesegroups can comprise alkyl, cycloalkyl, aryl, alkaryl, aralkyl orheterocyclic, which can be substituted with groups which aresubstantially inert to any component of the reaction mixture underconditions selected for preparation of the amido-amine. Such substituentgroups include hydroxy, halide (e.g., Cl, Fl, I, Br), --SH andalkylthio. When one or more of R¹⁰ through R¹⁴ are alkyl, such alkylgroups can be straight or branched chain, and will generally containfrom 1 to 20, more usually from 1 to 10, and preferably from 1 to 4,carbon atoms. Illustrative of such alkyl groups are methyl, ethyl,propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, dodecyl,tridecyl, hexadecyl, octadecyl and the like. When one or more of R¹⁰through R¹⁴ are aryl, the aryl group will generally contain from 6 to 10carbon atoms (e.g., phenyl, naphthyl).

When one or more of R¹⁰ through R¹⁴ are alkaryl, the alkaryl group willgenerally contain from about 7 to 20 carbon atoms, and preferably from 7to 12 carbon atoms. Illustrative of such alkaryl groups are tolyl,m-ethylphenyl, o-ethyltolyl, and m-hexyltolyl. When one or more of R¹⁰through R¹⁴ are aralkyl, the aryl component generally consists of phenylor (C₁ to C₆) alkyl-substituted phenol and the alkyl component generallycontains from 1 to 12 carbon atoms, and preferably from 1 to 6 carbonatoms. Examples of such aralkyl groups are benzyl, o-ethylbenzyl, and4-isobutylbenzyl. When one or more of R¹⁰ through R¹⁴ are cycloalkyl,the cycloalkyl group will generally contain from 3 to 12 carbon atoms,and preferably from 3 to 6 carbon atoms. Illustrative of such cycloalkylgroups are cyclopropyl, cyclobutyl, cyclohexyl, cyclooctyl, andcyclododecyl. When one or more of R¹⁰ through R¹⁴ are heterocyclic, theheterocyclic group generally consists of a compound having at least onering of 6 to 12 members in which one or more ring carbon atoms isreplaced by oxygen or nitrogen. Examples of such heterocyclic groups arefuryl, pyranyl, pyridyl, piperidyl, dioxanyl, tetrahydrofuryl, pyrazinyland 1,4-oxazinyl.

The alpha, beta ethylenically unsaturated carboxylate compounds employedherein have the following formula: ##STR10## wherein R¹⁰, R¹¹, R¹² andR¹³ are the same or different and are hydrogen or substituted orunsubstituted hydrocarbyl as defined above. Examples of such alpha,beta-ethylenically unsaturated carboxylate compounds of formula (XIV)are acrylic acid, methacrylic acid, the methyl, ethyl, isopropyl,n-butyl, and isobutyl esters of acrylic and methacrylic acids,2-butenoic acid, 2-hexenoic acid, 2-decenoic acid, 3-methyl-2-heptenoicacid, 3-methyl-2-butenoic acid, 3-phenyl-2-propenoic acid,3-cyclohexyl-2-butenoic acid, 2-methyl-2-butenoic acid,2-propyl-2-propenoic acid, 2-isopropyl-2-hexenoic acid,2,3-dimethyl-2-butenoic acid, 3-cyclohexyl-2-methyl-2-pentenoic acid,2-propenoic acid, methyl 2-propenoate, methyl 2-methyl-2-propenoate,methyl 2-butenoate, ethyl 2-hexenoate, isopropyl 2-decenoate, phenyl2-pentenoate, tertiary butyl 2-propenoate, octadecyl 2-propenoate,dodecyl 2-decenoate, cyclopropyl 2,3-dimethyl-2-butenoate, methyl3-phenyl-2-propenoate and the like.

The alpha, beta ethylenically unsaturated carboxylate thioestercompounds employed herein have the following formula: ##STR11## whereinR¹⁰, R¹¹, R¹² and R¹³ are the same or different and are hydrogen orsubstituted or unsubstituted hydrocarbyl as defined above. Examples ofsuch alpha, beta-ethylenically unsaturated carboxylate thioesters offormula (XV) are methylmercapto 2-butenoate, ethylmercapto 2-hexenoate,isopropylmercapto 2-decenoate, phenylmercapto 2-pentenoate, tertiarybutylmercapto 2-propenoate, octadecylmercapto 2-propenoate,dodecylmercapto 2-decenoate, cyclopropylmercapto2,3-dimethyl-2-butenoate, methylmercapto 3-phenyl-2-propenoate,methylmercapto 2-propenoate, methylmercapto 2-methyl-2-propenoate andthe like.

The alpha, beta-ethylenically unsaturated carboxyamide compoundsemployed herein have the following formula: ##STR12## wherein R¹⁰, R¹¹,R¹², R¹³ and R¹⁴ are the same or different and are hydrogen orsubstituted or unsubstituted hydrocarbyl as defined above. Examples ofalpha, beta-ethylenically unsaturated carboxyamides of Formula (XVI) are2-butenamide, 2-hexenamide, 2-decenamide, 3-methyl-2-heptenamide,3-methyl-2-butenamide, 3-phenyl-2-propenamide,3-cyclohexyl-2-butenamide, 2-methyl-2-butenamide,2-propyl-2-propenamide, 2-isopropyl-2-hexenamide,2,3-dimethyl-2-butenamide, 3-cyclohexyl-2-methyl-2-pentenamide, N-methyl2-butenamide, N,N-diethyl 2-hexenamide, N-isopropyl 2-decenamide,N-phenyl 2-pentenamide, N-tertiary butyl 2-propenamide, N-octadecyl2-propenamide, N-N-didodecyl 2-decenamide, N-cyclopropyl2,3-dimethyl-2-butenamide, N-methyl 3-phenyl-2-propenamide,2-propenamide, 2-methyl-2-propenamide, 2-ethyl-2-propenamide and thelike.

The alpha, beta ethylenically unsaturated thiocarboxylate compoundsemployed herein have the following formula: ##STR13## wherein R¹⁰, R¹¹,R¹², and R¹³ are the same or different and are hydrogen or substitutedor unsubstituted hydrocarbyl as defined above. Examples of alpha,beta-ethylenically unsaturated thiocarboxylate compounds of formula(XVII) are 2-butenthioic acid, 2-hexenthioic acid, 2-decenthioic acid,3-methyl-2-heptenthioic acid, 3-methyl-2-butenthioic acid,3-phenyl-2-propenthioic acid, 3-cyclohexyl-2-butenthioic acid,2-methyl-2-butenthioic acid, 2-propyl-2-propenthioic acid,2-isopropyl-2-hexenthioic acid, 2,3-dimethyl-2-butenthioic acid,3-cyclohexyl-2-methyl-2-pententhioic acid, 2-propenthioic acid, methyl2-propenthioate, methyl 2-methyl 2-propenthioate, methyl 2-butenthioate,ethyl 2-hexenthioate, isopropyl 2-decenthioate, phenyl 2-pententhioate,tertiary butyl 2-propenthioate, octadecyl 2-propenthioate, dodecyl2-decenthioate, cyclopropyl 2,3-dimethyl-2-butenthioate, methyl3-phenyl-2-propenthioate and the like.

The alpha, beta ethylenically unsaturated dithioic acid and acid estercompounds employed herein have the following formula: ##STR14## whereinR¹⁰, R¹¹, R¹² and R¹³, are the same or different and are hydrogen orsubstituted or unsubstituted hydrocarbyl as defined above. Examples ofalpha, beta-ethylenically unsaturated dithioic acids and acid esters offormula (XVIII) are 2-butendithioic acid, 2-hexendithioic acid,2-decendithioic acid, 3-methyl-2-heptendithioic acid,3-methyl-2-butendithioic acid, 3-phenyl-2-propendithioic acid,3-cyclohexyl-2-butendithioic acid, 2-methyl-2-butendithioic acid,2-propyl-2-propendithioic acid, 2-isopropyl-2-hexendithioic acid,2,3-dimethyl-2-butendithioic acid,3-cyclo-hexyl-2-methyl-2-pentendithioic acid, 2-propendithioic acid,methyl 2-propendithioate, methyl 2-methyl 2-propendithioate, methyl2-butendithioate, ethyl 2-hexendithioate, isopropyl 2-decendithioate,phenyl 2-pentendithioate, tertiary butyl 2-propendithioate, octadecyl2-propendithioate, dodecyl 2-decendithioate, cyclopropyl2,3-dimethyl-2-butendithioate, methyl 3-phenyl-2-propendithioate and thelike.

The alpha, beta ethylenically unsaturated thiocarboxyamide compoundsemployed herein have the following formula: ##STR15## wherein R¹⁰, R¹¹,R¹², R¹³ and R¹⁴ are the same or different and are hydrogen orsubstituted or unsubstituted hydrocarbyl as defined above. Examples ofalpha, beta-ethylenically unsaturated thiocarboxyamides of formula (XIX)are 2-butenthioamide, 2-hexenthioamide, 2-decenthioamide,3-methyl-2-heptenthioamide, 3-methyl-2-butenthioamide,3-phenyl-2-propenthioamide, 3-cyclohexyl-2-butenthioamide,2-methyl-2-butenthioamide, 2-propyl-2-propenthioamide,2-isopropyl-2-hexenthioamide, 2,3-dimethyl-2-butenthioamide,3-cyclohexyl-2-methyl-2-pententhioamide, N-methyl 2-butenthioamide,N,N-diethyl 2-hexenthioamide, N-isopropyl 2-decenthioamide, N-phenyl2-pententhioamide, N-tertiary butyl 2-propenthioamide, N-octadecyl2-propenthioamide, N-N-didodecyl 2-decenthioamide, N-cyclopropyl2,3-dimethyl-2-butenthioamide, N-methyl 3-phenyl-2-propenthioamide,2-propenthioamide, 2-methyl-2-propenthioamide, 2-ethyl-2-propenthioamideand the like.

Preferred compounds for reaction with the polyamines in accordance withthis invention are lower alkyl esters of acrylic and (lower alkyl)substituted acrylic acid. Illustrative of such preferred compounds arecompounds of the formula: ##STR16## where R¹² is hydrogen or a C₁ to C₄alkyl group, such as methyl, and R¹³ is hydrogen or a C₁ to C₄ alkylgroup, capable of being removed so as to form an amido group, forexample, methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, tert-butyl,aryl, hexyl, etc. In the preferred embodiments these compounds areacrylic and methacrylic esters such as methyl or ethyl acrylate, methylor ethyl methacrylate. When the selected alpha, beta-unsaturatedcompound comprises a compound of formula (XII) wherein X is oxygen, theresulting reaction product with the polyamine contains at least oneamido linkage (--C(O)N<) and such materials are herein termed"amido-amines". Similarly, when the selected alpha, beta unsaturatedcompound of Formula (XIII) comprises a compound wherein X is sulfur, theresulting reaction product with the polyamine contains thioamide linkage(--C(S)N<) and these materials are herein termed "thioamido-amines". Forconvenience, the following discussion is directed to the preparation anduse of amido-amines, although it will be understood that such discussionis also applicable to the thioamido-amines.

The type of amido-amine formed varies with reaction conditions. Forexample, a more linear amido-amine is formed where substantiallyequimolar amounts of the unsaturated carboxylate and polyamine arereacted. The presence of excesses of the ethylenically unsaturatedreactant of formula (XIII) tends to yield an amido-amine which is morecross-linked than that obtained where substantially equimolar amounts ofreactants are employed. Where, for economic or other reasons, across-linked amido-amine using excess amine is desired, generally amolar excess of the ethylenically unsaturated reactant of about at least10%, such as 10 to 300%, or greater, for example, 25 to 200%, isemployed. For more efficient cross-linking an excess of carboxylatedmaterial should preferably be used since a cleaner reaction ensues. Forexample, a molar excess of about 10 to 100% or greater such as 10 to50%, but preferably an excess of 30 to 50%, of the carboxylatedmaterial. Larger excess can be employed if desired.

In summary, without considering other factors, equimolar amounts ofreactants tend to produce a more linear amido-amine whereas excess ofthe formula (XIII) reactant tends to yield a more cross-linkedamido-amine. It should be noted that the higher the polyamine (i.e., ingreater the number of amino groups on the molecule) the greater thestatistical probability of cross-linking since, for example, atetraalkylenepentamine, such as tetraethylene pentamine ##STR17## hasmore labile hydrogens than ethylene diamine.

These amido-amine adducts so formed are characterized by both amido andamino groups. In their simplest embodiments they may be represented byunits of the following idealized formula: ##STR18## wherein the R¹⁵ 's,which may be the same or different, are hydrogen or a substituent group,such as a hydrocarbon group, for example, alkyl, alkenyl, alkynyl, aryl,etc., and A is a moiety of the polyamine which, for example, may bearyl, cycloalkyl, alkyl, etc., and n4 is an integer such as 1 to 10 orgreater.

The above simplified formula represents a linear amido-amine polymer.However, cross-linked polymers may also be formed by employing certainconditions since the polymer has labile hydrogens which can furtherreact with either the unsaturated moiety by adding across the doublebond or by amidifying with a carboxylate group.

Preferably, however, the amido-amines are not cross-linked to anysubstantial degree, and more preferably are substantially linear.

Preferably, the polyamine reactant contains at least one primary amine,and more preferably from 2 to 4 primary amines, group per molecule, andthe polyamine and the unsaturated reactant of formula (XIII) arecontacted in an amount of from about 1 to 10, more preferably from about2 to 6, and most preferably from about 3 to 5, equivalents of primaryamine in the polyamine reactant per mole of the unsaturated reactant offormula (XII).

The reaction between the selected polyamine and acrylate-type compoundis carried out at any suitable temperature. Temperatures up to thedecomposition points of reactants and products can be employed. Inpractice, one generally carries out the reaction by heating thereactants below 100° C., such as 80° C. to 90° C., for a suitable periodof time, such as a few hours. Where an acrylic-type ester is employed,the progress of the reaction can be judged by the removal of the alcoholin forming the amide.

During the early part of the reaction, alcohol is removed quite readilybelow 100° C. in the case of low boiling alcohols such as methanol orethanol. As the reaction slows, the temperature is raised to push thepolymerization to completion and the temperature may be raised to 150°C. toward the end of the reaction. Removal of alcohol is a convenientmethod of judging the progress and completion of the reaction which isgenerally continued until no more alcohol is evolved. Based on removalof alcohol, the yields are generally stoichiometric. In more difficultreactions, yields of at least 95% are generally obtained.

Similarly, it will be understood that the reaction of an ethylenicallyunsaturated carboxylate thioester of formula (XIII) liberates thecorresponding HSR¹³ compound (e.g., H₂ S when R¹³ is hydrogen) as aby-product, and of formula (14) liberates the corresponding HNR¹³ (R¹⁴compound (e.g., ammonia when R¹³ and R¹⁴ are each hydrogen) as aby-product.

The reaction time to form an amido-amine material can vary widelydepending on a wide variety of factors. For example, there is arelationship between time and temperature. In general, lower temperaturedemands longer times. Usually, reaction times of from about 2 to 30hours, such as 5 to 25 hours, and preferably 3 to 10 hours will beemployed. Although one can employ a solvent, the reaction can be runwithout the use of any solvent. In fact, where a high degree ofcross-linking is desired, it is preferably to avoid the use of a solventand most particularly to avoid a polar solvent such as water. However,taking into consideration the effect of solvent on the reaction, wheredesired, any suitable solvent can be employed, whether organic orinorganic, polar or non-polar.

As an example of the amido-amine adducts, the reaction of tetraethylenepentaamine (TEPA) with methyl methacrylate can be illustrated asfollows: ##STR19##

Tris(hydroxymethyl) amino methane (THAM) can be reacted with theaforesaid functionalized polymers to form amides, imides or ester typeadditives as taught by U.K. 984,409, or to form oxazoline compounds andborated oxazoline compounds as described, for example, in U.S. Pat. Nos.4,102,798; 4,116,876 and 4,113,639.

Derivatization Polymer From Alcohols

The functionalized polymers, particularly acid functionalized polymers,of the present invention can be reacted with alcohols, e.g. to formesters. The alcohols may be aliphatic compounds such as monohydric andpolyhydric alcohols or aromatic compounds such as phenols and naphthols.

The aromatic hydroxy compounds from which the esters may be derived areillustrated by the following specific examples: phenol, beta-naphthol,alpha- naphthol, cresol, resorcinol, catechol, p,p'di-hydroxybiphenyl,2-chlorophenol, 2,4-dibutylphenol, propene tetramer-substituted phenol,didodecylphenol, 4,4'-methylene-bis-phenol, alpha-decyl-beta-naphthol,polyisobutene (molecular weight of 1000)-substituted phenol, thecondensation product of heptylphenol with 0.5 mole of formaldehyde, thecondensation product of octyl-phenol with acetone,di(hydroxyphenyl)-oxide, di(hydroxy-phenyl)sulfide,di(hydroxyphenyl)disulfide, and 4-cyclo-hexylphenol. Phenol andalkylated phenols having up to three alkyl substituents are preferred.

The alcohols from which the esters may be derived preferably contain upto about 40 aliphatic carbon atoms. They may be monohydric alcohols suchas methanols, ethanol, isooctanol, dodecanol, cyclohexanol,cyclopentanol, behenyl alcohol, hexatriacontanol, neopentyl alcohol,isobutyl alcohol, benzyl alcohol, beta-phenyl-ethyl alcohol,2-methylcyclohexanol, beta-chloroethanol, monomethyl ether of ethyleneglycol, monobutyl ether of ethylene glycol, monopropyl ether ofdiethylene glycol, monododecyl ether of triethylene glycol, monooleateof ethylene glycol, monostearate of diethylene glycol, secpentylalcohol, tertbutyl alcohol, 5-bromo-dodecanol, nitro-octadecanol anddioleate of glycerol. The polyhydric alcohols preferably contain from 2to about 10 hydroxy radicals. They are illustrated by, for example,ethylene glycol, diethylene glycol, triethylene glycol, tetraethyleneglycol, dipropylene glycol, tripropylene glycol, dibutylene glycol,tributylene glycol, and other alkylene glycols in which the alkyleneradical contains from 2 to about 8 carbon atoms. Other useful polyhydricalcohols include glycerol, monooleate of glycerol, monostearate ofglycerol, monomethyl ether of glycerol, pentaerythritol, 9,10-dihydroxystearic acid, methyl ester of 9,10-dihydroxy stearic acid,1,2-butanediol, 2,3-hexanediol, 2,4-hexanediol, penacol, erythritol,arabitol, sorbitol, mannitol, 1,2-cyclo-hexanediol, and xylene glycol.Carbohydrates such as sugars, starches, cellulose, etc., likewise mayyield the esters of this invention. The carbohydrates may be exemplifiedby a glucose, fructose, sucrose, rhamnose, mannose, glyceraldehyde, andgalactose. Heterocyclic polyols, such as described in U.S. Pat. No.4,797,219, the disclosure of which is herein incorporated by reference,may be employed. Such polyols includetetrahydro-3,3,5,5-tetrakischydroxy-methyl)-4-pyranol also known asanhydroenneaheptitol(AEH)

A useful class of polyhydric alcohols are those having at least threehydroxy radicals, some of which have been esterified with amonocarboxylic acid having from about 8 to about 30 carbon atoms, suchas octanoic acid, oleic acid, stearic acid, linoleic acid, dodecanoicacid, or tall oil acid. Examples of such partially esterified polyhydricalcohols are the monooleate of sorbitol, distearate of sorbitol,monooleate of glycerol, monostearate of glycerol, di-dodecanoate oferythritol.

The esters may also be derived from unsaturated alcohols such as allylalcohol, cinnamyl alcohol, propargyl alcohol, 1-cyclohexene-3-ol, anoleyl alcohol. Still another class of the alcohols capable of yieldingthe esters of this invention comprise the ether-alcohols andamino-alcohols including, for example, the oxyalkylene-, oxyarylene-,amino-alkylene-, and amino-arylene-substituted alcohols having one ormore oxyalkylene, amino-alkylene or amino-arylene oxyarylene radicals.They are exemplified by Cellosolve, carbitol, phenoxyethanol,heptylphenyl-(oxypropylene)6-H, octyl-(oxyethylene)30-H,phenyl-(oxyoctylene)2-H, mono(heptyl-phenyl-oxypropylene)-substitutedglycerol, poly(styrene oxide), aminoethanol, 3-amino ethyl-pentanol,di(hydroxyethyl) amine, p-amino-phenol, tri(hydroxypropyl)amine,N-hydroxyethyl ethylene diamine, N,N,N',N'-tetrahydroxy-trimethylenediamine, and the like. For the most part, the ether-alcohols having upto about 150 oxyalkylene radicals in which the alkylene radical containsfrom 1 to about 8 carbon atoms are preferred.

The esters may be diesters, e.g., of succinic acids or acidic esters,i.e., partially esterified polyhydric alcohols or phenols, i.e., estershaving free alcoholic or phenolic hydroxyl radicals. Mixtures of theabove-illustrated esters likewise are contemplated within the scope ofthe invention.

The esters may be prepared by one of several methods. The method whichis preferred because of convenience and superior properties of theesters it produces, involves the reaction of a suitable alcohol orphenol with the acid or anhydride (i.e., functionalized polymer succinicanhydride). The esterification is usually carried out at a temperatureabove about 100° C., preferably between 150° C. and 300° C.

The water formed as a by-product is removed by distillation as theesterification proceeds. A solvent may be used in the esterification tofacilitate mixing and temperature control. It also facilitates theremoval of water from the reaction mixture. The useful solvents includexylene, toluene, diphenyl ether, chlorobenzene, and mineral oil.

A modification of the above process involving dicarboxylic acid involvesthe replacement of, for example, succinic anhydride with thecorresponding succinic acid as a functionalized compound. However,succinic acids readily undergo dehydration at temperatures above about100° C. and are thus converted to their anhydrides which are thenesterified by the reaction with the alcohol reactant. In this regard,succinic acids appear to be the substantial equivalents of theiranhydrides in the process.

The relative proportions of the acid functionalized polymer (e.g.,succinic acid functionalized polymer) and the hydroxy reactant which areto be used depend to a large measure upon the type of the productdesired, the functionality of the functionalized polymer, and the numberof hydroxyl groups present in the molecule of the hydroxy reactant. Forinstance, the formation of a half ester of a succinic acid, i.e., one inwhich only one of the two acid radicals is esterified, involves the useof one mole of a monohydric alcohol for each mole of the succinicfunctional group, whereas the formation of a diester of a succinic acidinvolves the use of two moles of the alcohol for each mole of the acidfunctional group. On the other hand, one mole of a hexahydric alcoholmay combine with as many as six moles of a di-acid to form an ester inwhich each of the six hydroxyl radicals of the alcohol is esterifiedwith one of the two acid radicals of the succinic acid. Thus, themaximum proportion of functional groups to be esterified with apolyhydric alcohol is determined by the number of hydroxyl groupspresent in the molecule of the hydroxy reactant. Esters obtained by thereaction of stoichiometric amounts of the acid reactant and hydroxyreactant are preferred.

In some instances, it is advantageous to carry out the esterification inthe presence of a catalyst such as sulfuric acid, pyridinehydrochloride, hydrochloric acid, benzenesulfonic acid,p-toluenesulfonic acid, phosphoric acid, or any other knownesterification catalyst. The amount of the catalyst in the reaction maybe as little as 0.01% (by weight of the reaction mixture), more oftenfrom about 0.1% to about 5%.

Ester derivatives likewise may be obtained by the reaction of a acidfunctionalized polymer with epoxide or a mixture of an epoxide andwater. Such reaction is similar to one involving the acid or anhydridewith a glycol. For instance, the product may be prepared by the reactionof functionalized polymer with alkylene oxide to yield half-esters,monoesters or diesters.

Epoxides which are commonly available for use in such reaction include,for example, ethylene oxide, propylene oxide, styrene oxide,1,2-butylene oxide, 2,3-butylene oxide, epichlorohydrin, cyclohexeneoxide, 1,2-octylene oxide, epoxidized soy bean oil, methyl ester of 9,10-epoxy-stearic acid, and butadiene monoepoxide. Preferred epoxides arethe alkylene oxides in which the alkylene radical has from 2 to about 8carbon atoms; or the epoxidized fatty acid esters in which the fattyacid radical has up to about 30 carbon atoms and the ester radical isderived from a lower alcohol having up to about 8 carbon atoms.

In lieu of the acid functionalized polymer, a polymer functionalizedwith lactone acid or an acid halide may be used in the processesillustrated above for preparing the ester derivatives of this invention.Such acid halides may be acid dibromides, acid dichlorides, acidmonochlorides, and acid monobromides.

In view of the above, the derivative compositions produced by reactingfunctionalized polymer with alcohols are esters including both acidicesters and neutral esters. Acidic esters are those in which less thanall of the functional groups in functionalized polymer are esterified,and hence possess at least one free functional group. Obviously, acidesters are easily prepared by using an amount of alcohol insufficient toesterify all of the functional groups in the functionalized polymer.

The functionalized, e.g., acid functionalized, polymers of thisinvention are reacted with the alcohols according to conventionalesterification techniques. This normally involves heating thefunctionalized polymer with the alcohol, optionally in the presence of anormally liquid, substantially inert, organic liquid solvent/diluentand/or in the presence of esterification catalyst. Temperatures of atleast about 100° C. up to the decomposition point are used (thedecomposition point having been defined hereinbefore). This temperatureis usually within the range of about 100° C. up to about 300° C. withtemperatures of about 140° C. to 250° C. often being employed.

Many issued patents disclose procedures for reacting high molecularweight carboxylic acids with alcohols to produce acidic esters andneutral esters. These same techniques are applicable to preparing estersfrom the functionalized polymer of this invention and the alcoholsdescribed above. All that is required is that the acylating reagents ofthis invention are substituted for the high molecular weight carboxylicacid acylating agents discussed in these patents, usually on anequivalent weight basis. The following U.S. Patents are expresslyincorporated herein by reference for their disclosure of suitablemethods for reacting the acylating reagents of this invention with thealcohols described above: U.S. Pat. Nos. 3,331,776; 3,381,022;3,522,179; 3,542,680; 3,697,428 and 3,755,169.

Derivatized Polymer From Mannich Base Condensation

The hydroxy aromatic functionalized polymer aldehyde/amino condensatesuseful as ashless dispersants in the compositions of this inventioninclude those generally referred to as Mannich condensates. Generallythey are made by reacting simultaneously or sequentially at least oneactive hydrogen compound such as a hydrocarbon-substituted phenol (e.g.,hydroxy aromatic functionalized polymer of the present invention),having at least one hydrogen atom bonded to an aromatic carbon, with atleast one aldehyde or aldehyde-producing material (typicallyformaldehyde precursor) and at least one amino or polyamino compoundhaving at least one NH group. Preferred phenolic compounds include thehydroxy aromatic functionalized polymer recited above. Useful aminecompounds can be selected from those recited above. The amine compoundsinclude primary or secondary monoamines having hydrocarbon substituentsof 1 to 30 carbon atoms or hydroxyl-substituted hydrocarbon substituentsof 1 to about 30 carbon atoms. Another type of typical amine compoundare the polyamines described during the discussion of the acylatednitrogen-containing compounds. The materials described in the followingpatents are illustrative of Mannich dispersants: U.S. Pat. Nos.3,413,347; 3,697,574; 3,725,277; 3,725,480; 3,726,882; 4,454,059 and5,102,566.

The following U.S. patents contain extensive descriptions of Mannichcondensates which can be used in making the compositions of thisinvention:

    ______________________________________                                        U.S. Pat. Nos.                                                                ______________________________________                                        2,459,112      3,413,347    3,558,743                                         2,962,442      3,442,808    3,586,629                                         2,984,550      3,448,047    3,591,598                                         3,036,003      3,454,497    3,600,372                                         3,166,516      3,459,661    3,634,515                                         3,236,770      3,461,172    3,649,229                                         3,355,270      3,493,520    3,697,574                                         3,368,972      3,539,633    5,017,299                                         ______________________________________                                    

Condensates made from sulfur-containing reactants also can be used inthe compositions of the present invention. Such sulfur-containingcondensates are described in U.S. Pat. Nos. 3,368,972; 3,649,229;3,600,372; 3,649,659 and 3,741,896. These patents also disclosesulfur-containing Mannich condensates.

The Aldehyde Material Used in Mannich Condensations

The aldehyde reactants will generally comprise formaldehyde orparaformaldehyde, although it will be understood that other aldehydegroup-containing compounds, such as C₂ to C₁₀ hydrocarbyl aldehydes(e.g., butyraldehyde, acetaldehyde, propionaldehyde, and the like) canalso be employed. A preferred group of aldehyde materials are compoundsof the formula: R¹⁶ CHO, wherein R¹⁶ is H or aliphatic hydrocarbonradicals having from 1 to 4 carbon atoms.

Mannich Base Condensation Derivatives

The Mannich Base condensate dispersants are prepared by condensing atleast one of the above-described hydroxy/aromatic functionalizedpolymers with an amine, which can include amines as described, in thepresence of an aldehyde. The reactants are contacted for a time andunder conditions sufficient to form the desired dispersant product.

The process employed in the condensation reaction can be any of thosedisclosed in U.S. Pat. Nos. 3,634,515; 3,649,229; 3,442,808; 3,798,165;3,798,247 and 3,539,633, the disclosures of which are herebyincorporated by reference in their entirety.

The amount of the reactants employed is not critical and can vary over awide range. It is, however, preferred to react the hydroxy aromaticfunctionalized polymer, aldehyde reactant and amine compound in therespective molar ratios of about 1:(1 to 4):(0.1 to 10). An excess ofaldehyde reactant may be used. More specifically, condensates can beprepared by reacting about one molar portion of phenolic polymer withabout 1 to about 2 molar portions of aldehyde and about 1 to about 5equivalent portions of amino compound (an equivalent of amino compoundis its molecular weight divided by the number of ═NH groups present).The conditions under which such condensation reactions are carried outare well known to those skilled in the art as evidenced by theabove-noted patents. Therefore, these patents are also incorporated byreference for their disclosures relating to reaction conditions.

The reactions are exothermic, but it is desirable to heat the reactionto a temperature of above about 150° C., preferably in the range of fromabout 150° C. to 200° C. This additional heating drives the reaction tocompletion and removes water from the resultant condensation reactionproduct.

The condensation reaction can be illustrated by the following reactionsemploying an alkylene polyamine and formaldehyde: ##STR20## wherein "z",and P are as defined above.

A useful group of Mannich Base ashless dispersants are those formed bycondensing phenol functionalized polymer with formaldehyde andpolyethylene amines, e.g., tetraethylene pentamine, pentaethylenehexamine, polyoxyethylene and polyoxypropylene amines, e.g.,polyoxypropylene diamine and combinations thereof. One particularlypreferred dispersant comprises a condensation of (A) phenolfunctionalized polymer, (B) formaldehyde, (C) a polyoxyalkylenepolyamine, e.g., polyoxypropylene diamine, and (D) a polyalkylenepolyamine, e.g. polyethylene diamine and tetraethylene pentamine, usingabout 2 to about 8 moles each of (B) and about 1 to about 4 moles of (C)or (D) per mole of (A).

A useful class of nitrogen-containing condensation products for use inthe present invention are those made by a "2-step process" as disclosedin U.S. Pat. No. 4,273,891, incorporated herein by reference. Briefly,these nitrogen-containing condensates are made by (1) reacting at leastphenol functionalized polymer of the present invention with a loweraliphatic C₁ to C₇ aldehyde or reversible polymer thereof in thepresence of an alkaline reagent, such as an alkali metal hydroxide, at atemperature up to about 150° C.; (2) substantially neutralizing theintermediate reaction mixture thus formed; and (3) reacting theneutralized intermediate with at least one compound which contains anamino group having at least one -NH- group. These 2-step condensates canbe made from (a) phenol functionalized polymer and (b) formaldehyde, orreversible polymer thereof, (e.g., trioxane, paraformaldehyde) orfunctional equivalent thereof, (e.g., methylol) and (c) an alkylenepolyamine such as ethylene polyamines having between 2 and 10 nitrogenatoms.

Derivatized Polymer From Reactive Metals/Metal Compounds

Useful reactive metals or reactive metal compounds are those which willform metal salts or metal-containing complexes with the functionalizedpolymer. Metal complexes are typically achieved by reacting thefunctionalized polymers with amines and/or alcohols as discussed aboveand also with complex forming reactants either during or subsequent toamination.

Reactive metal compounds for use in the formation of complexes with thereaction products of functionalized polymer and amines include thosedisclosed in U.S. Pat. No. 3,306,908. Complex-forming metal reactantsinclude the nitrates, nitrites, halides, carboxylates, phosphates,phosphites, sulfates, sulfites, carbonates, borates, and oxides ofcadmium as well as metals having atomic numbers from 24 to 30 (includingchromium, manganese, iron, cobalt, nickel, copper and zinc). Thesemetals are the so-called transition or coordination metals, i.e., theyare capable of forming complexes by means of their secondary orcoordination valence. Specific examples of the complex-forming metalcompounds useful as the metal reactant are cobaltous nitrate, cobaltousoxide, cobaltic oxide, cobalt nitrite, cobaltic phosphate, cobaltouschloride, cobaltic chloride, cobaltous carbonate, chromous acetate,chromic acetate, chromic bromide, chromous chloride, chromic fluoride,chromous oxide, chromium dioxide, chromic oxide, chromic sulfite,chromous sulfate heptahydrate, chromic sulfate, chromic formate, chromichexanoate, chromium oxychloride, chromic phosphite, manganous acetate,manganous benzoate, manganous carbonate, manganese dichloride, manganesetrichloride, manganous citrate, manganous formate, manganous nitrate,manganous oxalate, manganese monooxide, manganese dioxide, manganesetrioxide, manganese heptoxide, manganic phosphate, manganouspyrophosphate, manganic metaphosphate, manganous hypophosphite,manganous valerate, ferrous acetate, ferric benzoate, ferrous bromide,ferrous carbonate, ferric formate, ferrous lactate, ferrous nitrate,ferrous oxide, ferric oxide, ferric hypophosphite, ferric sulfate,ferrous sulfite, ferric hydrosulfite, nickel dibromide, nickeldichloride, nickel nitrate, nickel dioleate, nickel stearate, nickelsulfite, cupric propionate, cupric acetate, cupric metaborate, cupricbenzoate, cupric formate, cupric laurate, cupric nitrite; cupricoxychloride, cupric palmitate, cupric salicylate, zinc benzoate, zincborate, zinc bromide, zinc chromate, zinc dichromate, zinc iodide, zinclactate, zinc nitrate, zinc oxide, zinc stearate, zinc sulfite, cadmiumbenzoate, cadmium carbonate, cadmium butyrate, cadmium chloroacetate,cadmium fumarate, cadmium nitrate, cadmium dihydrogenphosphate, cadmiumsulfite, and cadmium oxide. Hydrates of the above compounds areespecially convenient for use in the process of this invention.

U.S. Pat. No. 3,306,908 is expressly incorporated herein by referencefor its discussion of reactive metal compounds suitable for forming suchcomplexes and its disclosure of processes for preparing the complexes.Basically, those processes are applicable to the carboxylic derivativecompositions of the functionalized polymer of this invention with theamines as described above by substituting, or on an equivalent basis,the functionalized polymer of this invention with the high molecularweight carboxylic acid functionalized polymer disclosed in U.S. Pat. No.3,306,908.

U.S. Pat. No. Re. 26,433 discloses metals useful in preparing salts fromacid functionalized polymer and/or an amine derivatized polymer asdescribed hereinabove. Metal salts are prepared, according to thispatent, from alkali metals, alkaline earth metals, zinc, cadmium, lead,cobalt and nickel. Examples of a reactive metal compound suitable foruse are sodium oxide, sodium hydroxide, sodium carbonate, sodiummethylate, sodium propylate, sodium pentylate, sodium phenoxide,potassium oxide, potassium hydroxide, potassium carbonate, potassium ismethylate, potassium pentylate, potassium phenoxide, lithium oxide,lithium hydroxide, lithium carbonate, lithium pentylate, calcium oxide,calcium hydroxide, calcium carbonate, calcium methylate, calciumethylate, calcium propylate, calcium chloride, calcium fluoride, calciumpentylate, calcium phenoxide, calcium nitrate, barium oxide, bariumhydroxide, barium carbonate, barium chloride, barium fluoride, bariummethylate, barium propylate, barium pentylate, barium nitrate, magnesiumoxide, magnesium hydroxide, magnesium carbonate, magnesium ethylate,magnesium propylate, magnesium chloride, magnesium bromide, barium,iodide, magnesium phenoxide, zinc oxide, zinc hydroxide, zinc carbonate,zinc methylate, zinc propylate, zinc pentylate, zinc chloride, zincfluoride, zinc nitrate trihydrate, cadmium oxide, cadmium hydroxide,cadmium carbonate, cadmium methylate, cadmium propylate, cadmiumchloride, cadmium bromide, cadmium fluoride, lead oxide, lead hydroxide,lead carbonate, lead ethylate, lead pentylate, lead chloride, leadfluoride, lead iodide, lead nitrate, nickel oxide, nickel hydroxide,nickel carbonate, nickel chloride, nickel bromide, nickel fluoride,nickel methylate, nickel pentylate, nickel nitrate hexahydrate, cobaltoxide, cobalt hydroxide, cobaltous bromide, cobaltous chloride, cobaltbutylate, cobaltous nitrate hexahydrate, etc. The above metal compoundsare merely illustrative of those useful in this invention and theinvention is not to be considered as limited to such.

U.S. Pat. No. Re. 26,433 is expressly incorporated herein by referencefor its disclosure of useful reactive metal compounds as, and processesfor, utilizing these compounds in the formation of salts. Again, inapplying the teachings of this patent to the present invention, it isonly necessary to substitute the functionalized polymer of thisinvention on an equivalent weight basis for the high molecular weightcarboxylic acylating agents disclosed in this reissue patent.

U.S. Pat. No. 3,271,310 discloses the preparation of metal salt of highmolecular weight carboxylic acid material, in particular alkenylsuccinic acids which can be adapted to make the present functionalizedpolymer. The metal salts disclosed therein are acid salts, neutralsalts, and basic salts. Among the illustrative reactive metal compoundsused to prepare the acidic, neutral and basic salts of the acidfunctionalized polymer are those disclosed in U.S. Pat. No. 3,271,310including lithium oxide, lithium hydroxide, lithium carbonate, lithiumpentylate, sodium oxide, sodium hydroxide, sodium carbonate, sodiummethylate, sodium propylate, sodium phenoxide, potassium oxide,potassium hydroxide, potassium carbonate, potassium methylate, silveroxide, silver carbonate, magnesium oxide, magnesium hydroxide, magnesiumcarbonate, magnesium ethylate, magnesium propylate, magnesium phenoxide,calcium oxide, calcium hydroxide, calcium carbonate, calcium methylate,calcium propylate, calcium pentylate, zinc oxide, zinc hydroxide, zinccarbonate, zinc propylate, strontium oxide, strontium hydroxide, cadmiumoxide, cadmium hydroxide, cadmium carbonate, cadmium ethylate, bariumoxide, barium hydroxide, barium hydrate, barium carbonate, bariumethylate, barium pentylate, aluminum oxide, aluminum propylate, leadoxide, lead hydroxide, lead carbonate, tin oxide, tin butylate, cobaltoxide, cobalt hydroxide, cobalt carbonate, cobalt pentylate, nickeloxide, nickel hydroxide, and nickel carbonate. The present invention isnot to be considered as limited to the use of the above metal compounds;they are presented merely to illustrate the metal compounds includedwithin the invention.

U.S. Pat. No. 3,271,310 is expressly incorporated herein by referencefor its disclosure of suitable reactive metal compounds suitable forforming salts of the functionalized polymer of this invention as well asillustrative processes for preparing salts of these reagents. As will beapparent, the processes of U.S. Pat. No. 3,271,310 are applicable tothis invention merely by substituting on an equivalent weight basis, thefunctionalized polymer of this invention for the high molecular weightcarboxylic acids of the patent.

Derivatization Reactant Ratios

From the foregoing description, it is apparent that the appropriatefunctionalized polymer of this invention can be reacted with anyindividual derivatizing compound such as amine, alcohol, reactive metal,reactive metal compound or any combination of two or more of any ofthese; that is, for example, one or more amines, one or more alcohols,one or more reactive metals or reactive metal compounds, or a mixture ofany of these. The mixture can be a mixture of two or more amines, amixture of two or more alcohols, a mixture of two or more metals orreactive metal compounds, or a mixture of two or more componentsselected from amines and alcohols, from amines and reactive metals orreactive metal compounds, from alcohols and reactive metal compounds, orone or more components from each of the amines, alcohols, and reactivemetals or reactive metal compounds. Furthermore, the appropriatefunctionalized polymer of this invention can be reacted with the amines,alcohols, reactive metals, reactive metal compounds, or mixturesthereof, as described above, simultaneously (concurrently) orsequentially in any order of reaction.

In any of the foregoing derivatizing reactions involving the use of thefunctionalized polymer of this invention, substantially inert organicliquid diluents may be used to facilitate mixing, temperature control,and handling of the reaction mixture. Suitable diluents includealiphatic, cycloaliphatic, and aromatic hydrocarbons as well as thecorresponding halogenated hydrocarbons, particularly chlorinatedhydrocarbons. These diluents are exemplified by benzene, toluene,xylene, chlorobenzenes, hexane, heptane, cyclohexane, or mixtures ofthese. Mineral oils particularly low viscosity mineral oils are verygood diluents. Other organic solvents can also be employed such asethers, sulfoxide, sulfones, and the like. Where one or more of thereactants themselves are liquid at the reaction temperature, thereactant itself functions as a diluent and it may be convenientsometimes to employ an excess amount of the reactant to serve thispurpose.

The following discussion is intended to explain and illustrate what ismeant by the term "equivalent" with respect to various classes ofreactants as the term is used herein. As will be shown a "derivatizingratio" is defined as the molar equivalent ratios of the functionalizedpolymer to derivatizing compound.

The number of equivalents which characterize the functionalized polymerof the invention depends upon the number of functional groups presentwithin the structure thereof as expressed by its functionality (F*).

Thus, a functionalized polymer having a functionality (F*) of 3 has anaverage of three equivalents per mole. Alternatively, 6,000 M_(n)polymer functionalized with mono acid to a functionality of 3 possessesan equivalent weight of 2000 per mole.

A nitrogen-containing derivatizing compound such as an amine reactant,is regarded as having a number of equivalents per mole corresponding tothe average number of reactive amine groups, i.e., primary or secondaryamine groups, per molecule. Thus, ammonia has one equivalent per mole;urea, hydrazine, ethylenediamine, and piperazine have two equivalentsper mole; and tetraethylene pentamine has five equivalents per mole.Mixtures of nitrogen-containing reactants such as mixtures of alkylenepolyamines are regarded as having an equivalent weight equal to theweight of the mixture divided by the number of reactive nitrogen atomspresent. For example, 1,000 parts of a polyethylene polyamine mixturecontaining 37 percent by weight nitrogen has an equivalent weight ofabout 38.

In like manner, hydroxyaromatic compounds and alcohols have equivalentweights equal to their molecular weights divided by the number offunctional --OH groups per molecule. Or, from another viewpoint, theypossess a number of equivalents per mole equal to the number of --OHgroups. Thus, pentaerythritol has four equivalents per mole and anequivalent weight of 34. Phenol has one equivalent per mole so that itsequivalent weight equals its molecular weight.

Metal reactants have an equivalent weight equal to their molecularweight divided by the product of the number of metal atoms per moleculeof reactant times the valence of the metal. Since most of the metalreactants have only one metal per atom per molecule, the equivalentweight of the metal reactant is normally the molecular weight divided bythe valence of the metal. Stated differently, a metal reactant normallyhas a number of equivalents per mole equal to the valence of the metal.For example, calcium hydroxide, zinc chloride, and barium oxide have twoequivalents per mole; sodium hydroxide and lithium hydroxide have oneequivalent per mole.

From what has been said hereinabove, it will be apparent to thoseskilled in the art that the reaction products produced by reactingfunctionalized polymer of this invention with derivatizing compoundssuch as alcohols, nitrogen-containing reactants, metal reactants, andthe like will, in fact, be mixtures of various reaction products. Thisis especially apparent in view of the fact that the functionalizedpolymers themselves can be mixtures of materials. For example, if acidfunctionalized polymer is reacted with a polyol, the esterificationproduct can contain esters wherein only one hydroxyl group has beenesterified, esters wherein two or more of the hydroxy groups have beenesterified by the same or different functionalized polymer, esters whereall of the carboxyl groups of an acid functionalized polymer have beenesterified, esters where less than all of the carboxyl groups offunctionalized polymer have been esterified, and the like. However, forpurposes of the present invention it is not necessary to know thespecific structure of each derivatized component of the reactionmixtures produced, since it is not necessary to isolate these componentsin order to use them as additives, e.g., in lubricants and fuels.

While the functionalized polymers themselves possess some dispersantcharacteristics and can be used as dispersant additives in lubricantsand fuels, best results are achieved when at least about 30, preferably,at least about 50, most preferably 100% of the functional groups arederivatized. Furthermore, it is not necessary that all the functionalgroups of the functionalized polymer be derivatized to the same productor even the same type of product. Thus, functionalized polymer may befirst reacted with one or more alcohols to convert a portion of the acidfunctional groups to ester groups and thereafter this ester product canbe reacted with one or more amines and/or one or more metal reactants toconvert all or a portion of the remaining carboxyl functions to aderivatized amine groups such as amides, imides, amidines, amine saltgroups, and the like or metal salt groups.

In view of the above, the "derivatization ratio" can vary considerably,depending, e.g., on the reactants and type of bonds sought to be formed.Thus, while any derivatization ratio effective to impart the desiredproperties to the derivatized polymer can be employed, it iscontemplated that such effective ratios will range typically from about0.05:1 to about 4:1, preferably 0.5:1 to about 2.0:1 (e.g. 0.6:1 toabout 1.5:1) and most preferably 0.7:1 to about 1:1 (e.g. 0.8:1 to0.9:1). As can be seen from the above ratios it is preferred to employan excess of derivatizing compound particularly where the unreactedexcess thereof can be easily stripped from the reaction mixture.

Post Treatment

Another aspect of this invention involves the post treatment ofderivatized polymer. The processes for post-treating derivatized polymerare analogous to the post-treating processes used with respect toconventional dispersants and conventional multi-functional viscosityimprovers of the prior art. Accordingly, the same reaction conditions,ratio of reactants and the like can be used. Reference is made to U.S.Pat. No. 5,017,199.

Accordingly, derivatized polymer can be post-treated with such reagentsas urea, thiourea, carbon disulfide, aldehydes, ketones, carboxylicacids, hydrocarbon-substituted succinic anhydrides, nitriles, epoxides,boron compounds, phosphorus compounds or the like. Exemplary materialsof this kind are described in the following U.S. Pat. Nos. 3,036,003;3,200,107; 3,254,025; 3,278,550; 3,281,428; 3,282,955; 3,366,569;3,373,111; 3,442,808; 3,455,832; 3,493,520; 3,513,093; 3,539,633;3,579,450; 3,600,372; 3,639,242; 3,649,659; 3,703,536 and 3,708,522which are herein incorporated by reference.

The amine derivatized polymers of the present invention as describedabove can be post-treated, particularly for use as dispersants andviscosity index improvers by contacting said polymers with one or morepost-treating reagents selected from the group consisting of boronoxide, boron oxide hydrate, boron halides, boron acids, esters of boronacids, carbon disulfide, sulfur, sulfur chlorides, alkenyl cyanides,aldehydes, ketones, urea, thiourea, guanidine, dicyanodiamide,hydrocarbyl phosphates, hydrocarbyl phosphites, hydrocarbylthiophosphates, hydrocarbyl thiophosphites, phosphorus sulfides,phosphorus oxides, phosphoric acid, hydrocarbyl thiocyanates,hydrocarbyl isocyanates, hydrocarbyl isothiocyanates, epoxides,episulfides, formaldehyde or formaldehyde-producing compounds plusphenols, and sulfur plus phenols, and C₁ to C₃₀ hydrocarbyl substitutedsuccinic acids and anhydrides (e.g., succinic anhydride, dodecylsuccinic anhydride and the like), fumaric acid, itaconic acid, maleicacid, maleic anhydride, chloromaleic acid, chloromaleic anhydride,acrylic acid, methacrylic acid, crotonic acid, cinnamic acid, and loweralkyl (e.g., C₁ to C₄ alkyl) acid esters of the foregoing, e.g., methylmaleate, ethyl fumarate, methyl fumarate, and the like.

For example, the amine derivatized polymers can be treated with a boroncompound selected from the class consisting of boron oxide, boronhalides, boron acids and esters of boron acids in an amount to providefrom about 0.1 atomic proportion of boron for each mole of said nitrogencomposition to about 20 atomic proportions of boron for each atomicproportion of nitrogen of said nitrogen composition. Borated derivatizedpolymer useful as dispersants can contain from about 0.05 to 2.0 wt. %,e.g. 0.05 to 0.7 wt. % boron based on the total weight of said boratednitrogen-containing dispersant compound. The boron, which appears to bein the product as dehydrated boric acid polymers (primarily (HBO₂)₃), isbelieved to attach to the derivatized polymer as amine salts, e.g., themetaborate salt of said amine derivatized polymers.

Treating is readily carried out by adding from about 0.05 to 4, e.g. 1to 3 wt. % (based on the weight of said derivatized polymer) of saidboron compound, preferably boric acid which is most usually added as aslurry to said nitrogen compound and heating with stirring at from about135° C. to 190° C., e.g. 140° C. to 170° C., for from 1 to 5 hoursfollowed by nitrogen stripping at said temperature ranges.

Since post-treating processes involving the use of these post-treatingreagents is known insofar as application to high molecular weightnitrogen-containing dispersants of the prior art, further descriptionsof these processes herein is unnecessary. In order to apply the priorart processes to the compositions of this invention, all that isnecessary is that reaction conditions, ratio of reactants, and the likeas described in the prior art, be applied to the novel compositions ofthis invention. The following U.S. patents are expressly incorporatedherein by reference for their disclosure of post-treating processes andpost-treating reagents applicable to the compositions of this invention:U.S. Pat. Nos. 3,087,936; 3,200,107; 3,254,025; 3,256,185; 3,278,550;3,281,428; 3,282,955; 3,284,410; 3,338,832; 3,344,069; 3,366,569;3,373,111; 3,367,943; 3,403,102; 3,428,561; 3,502,677; 3,513,093;3,533,945; 3,541,012; 3,639,242; 3,708,522; 3,859,318; 3,865,813;3,470,098; 3,369,021; 3,184,411; 3,185,645; 3,245,908; 3,245,909;3,245,910; 3,573,205; 3,692,681; 3,749,695; 3,865,740; 3,954,639;3,458,530; 3,390,086; 3,367,943; 3,185,704; 3,551,466; 3,415,750;3,312,619; 3,280,034; 3,718,663; 3,652,616; UK Patent No. 1,085,903; UKPatent No. 1,162,436; U.S. Pat. No. 3,558,743. Particularly preferredfor post-treating is the process disclosed in commonly assigned U.S.Ser. No. 992,413 filed Dec. 17, 1992 entitled Improved Low SedimentProcess for Forming Borated Dispersant, Docket No. PT-849.

The derivatized polymers of the present invention can also be treatedwith polymerizable lactones (such as epsilon-caprolactone) to formdispersant adducts having the moiety --[C(O)(C₂)_(z) O]_(m) H, wherein zis a number of from 4 to 8 (e.g., 5 to 7) and m has an average value offrom about 0 to 100 (e.g., 0.2 to 20). The derivatized polymers of thisinvention, particularly for use as a dispersant, can be post-treatedwith a C₅ to C₉ lactone, e.g., epsilon-caprolactone, by heating amixture of the polymers and lactone in a reaction vessel in the absenceof a solvent at a temperature of about 50° C. to about 200° C., morepreferably from about 75° C. to about 180° C., and most preferably fromabout 90° C. to about 160° C., for a sufficient period of time to effectreaction. Optionally, a solvent for the lactone, dispersant materialand/or the resulting adduct may be employed to control viscosity and/orthe reaction rates.

In one preferred embodiment, the C₅ to C₉ lactone, e.g.,epsilon-caprolactone, is reacted with a nitrogen containing polymer(i.e., dispersant) in a 1:1 mole ratio of lactone to dispersantmaterial. In practice, the ratio of lactone to polymer may varyconsiderably as a means of controlling the length of the sequence of thelactone units in the adduct. For example, the mole ratio of the lactoneto the dispersant material may vary from about 10:1 to about 0.1:1, morepreferably from about 5:1 to about 0.2:1, and most preferably from about2:1 to about 0.4:1. It is preferable to maintain the average degree ofpolymerization of the lactone monomer below about 100, with a degree ofpolymerization on the order of from about 0.2 to about 50 beingpreferred, and from about 0.2 to about 20 being more preferred. Foroptimum dispersant performance the nitrogen containing polymer as adispersant, sequences of from about 1 to about 5 lactone units in a roware preferred.

Catalysts useful in the promotion of the lactone-dispersant materialreactions are selected from the group consisting of stannous octanoate,stannous hexanoate, tetrabutyl titanate, a variety of organic-based acidcatalysts and amine catalysts, as described on page 266, and forward, ina book chapter authored by R. D. Lundberg and E. F. Cox, entitled"Kinetics and Mechanisms of Polymerization: Ring OpeningPolymerization", edited by Frisch and Reegen, published by Marcel Dekkerin 1969, wherein stannous octanoate is an especially preferred catalyst.The catalyst is added to the reaction mixture at a concentration levelof about 50 to about 10,000 parts per weight of catalyst per one millionparts of the total reaction mixture.

Exemplary of adducts formed by reaction of dispersant materials of thisinvention and epsilon-caprolactone are those adducts illustrated by thefollowing equation: ##STR21## wherein m and P are as defined above. R*can be H, a hydrocarbon of 1 to 18 5 carbons, or a halogen. Thereactions of such lactones with dispersant materials containing nitrogenor ester groups is more completely described in U.S. Pat. Nos.4,906,394; 4,866,141; 4,866,135; 4,866,140; 4,866,142; 4,866,139 and4,963,275, the disclosure of each of which is hereby incorporated byreference in its entirety.

Lubricating Compositions

The above discussions relate to a variety of materials including thepolymer per se, functionalized polymer, the derivatized polymer, andpost-treated derivatized polymer.

The polymer per se may be used as a synthetic base oil. Thefunctionalized polymer, in addition to acting as intermediates fordispersant manufacture, can be used as a molding release agent, moldingagent, metal working lubricant, point thickener and the like.

The primary utility for all the above-described material, from polymerall the way through post-treated derivatized polymer, is as an additivefor oleaginous compositions. For ease of discussion the above-mentionedmaterials are collectively and individually referred to herein asadditives when used in the context of an oleaginous compositioncontaining such "additives".

Accordingly, the additives of the present invention may be used byincorporation and dissolution into an oleaginous material such as fuelsand lubricating oils. When the additives of this invention are used innormally liquid petroleum fuels such as middle distillates boiling fromabout 65° C. to 430° C., including kerosene, diesel fuels, home heatingfuel oil, jet fuels, etc., a concentration of the additives in the fuelin the range of typically from about 0.001 to about 0.5, and preferably0.005 to about 0.15 wt. %, based on the total weight of the composition,will usually be employed. Useful compositions and additives aredisclosed in U.S. Pat. No. 5,102,566, hereby incorporated by reference.

The additives of the present invention find their primary utility inlubricating oil compositions which employ a base oil in which theadditives are dissolved or dispersed therein. Such base oils may benatural or synthetic. Base oils suitable for use in preparing thelubricating oil compositions of the present invention include thoseconventionally employed as crankcase lubricating oils for spark-ignitedand compression-ignited internal combustion engines, such as automobileand truck engines, marine and railroad diesel engines, and the like.Advantageous results are also achieved by employing the additivemixtures of the present invention in base oils conventionally employedin and/or adapted for use as power transmitting fluids, universaltractor fluids and hydraulic fluids, heavy duty hydraulic fluids, powersteering fluids and the like. Gear lubricants, industrial oils, pumpoils and other lubricating oil compositions can also benefit from theincorporation therein of the additives of the present invention.

These lubricating oil formulations conventionally contain severaldifferent types of additives that will supply the characteristics thatare required in the formulations. Among these types of additives areincluded viscosity index improvers, antioxidants, corrosion inhibitors,detergents, dispersants, pour point depressants, antiwear agents,friction modifiers, etc.

The additives of the present invention, particularly those adapted foruse as dispersants, can be incorporated into a lubricating oil in anyconvenient way. Thus, they can be added directly to the oil bydispersing or dissolving the same in the oil at the desired level ofconcentrations of the additive. Such blending into the additional lubeoil can occur at room temperature or elevated temperatures.Alternatively, the additives can be blended with a suitable oil-solublesolvent and base oil to form a concentrate, and then blending theconcentrate with a lubricating oil basestock to obtain the finalformulation. Such dispersant concentrates will typically contain (on anactive ingredient (AI) basis) from about 10 to about 80 wt. %, typicallyabout 20 to about 60 wt. %, and preferably from about 40 to about 50 25wt. %, additive, and typically from about 40 to 80 wt. %, preferablyfrom about 40 to 60 wt. %, base oil, i.e., hydrocarbon oil based on theconcentrate weight. The lubricating oil basestock for the additivetypically is adapted to perform a selected function by the incorporationof additional additives therein to form lubricating oil compositions(i.e., formulations).

Usually these concentrates may be diluted with 3 to 100, e.g., 5 to 40parts by weight of lubricating oil, per part by weight of the additivepackage, in forming finished lubricants, e.g. crankcase motor oils. Thepurpose of concentrates, of course, is to make the handling of thevarious materials less difficult and awkward as well as to facilitatesolution or dispersion in the final blend. Thus, the additives of thepresent invention and formulations containing them would usually beemployed in the form of a 40 to 50 wt. % concentrate, for example, in alubricating oil fraction.

The additives of the present invention will be generally used inadmixture with a lube oil basestock, comprising an oil of lubricatingviscosity, including natural and synthetic lubricating oils and mixturesthereof. Useful oils are described in U.S. Pat. Nos. 5,017,299 and5,084,197.

Natural oils include animal oils and vegetable oils (e.g., castor, lardoil) liquid petroleum oils and hydrorefined, solvent-treated oracid-treated mineral lubricating oils of the paraffinic, naphthenic andmixed paraffinic-naphthenic types. Oils of lubricating viscosity derivedfrom coal or shale are also useful base oils.

Synthetic lubricating oils include hydrocarbon oils and halosubstitutedhydrocarbon oils such as polymerized and interpolymerized olefins (e.g.,polybutylenes, polypropylenes, propylene-isobutylene copolymers,chlorinated polybutylenes, etc.) poly(hexenes), poly(1-octenes),poly(1-decenes), etc. and mixtures thereof; alkylbenzenes (e.g.,dodecyl-benzenes, tetradecyl-benzenes, dinonylbenzenes,di-(2-ethylhexyl)-benzenes, etc.); polyphenyls (e.g., biphenyls,terphenyls, alkylated diphenyl ethers and alkylated diphenyl sulfidesand the derivatives, analogs and homologs thereof and the like.

Alkylene oxide polymers and interpolymers and derivatives thereof wherethe terminal hydroxyl groups have been modified by esterification,etherification, etc., constitute another class of known syntheticlubricating oils. These are exemplified by polyoxyalkylene polymersprepared by polymerization of ethylene oxide or propylene oxide, thealkyl and aryl ethers of these polyoxyalkylene polymers (e.g.,methyl-poly isopropylene glycol ether having an average molecular weightof 1000, diphenyl ether of polyethylene glycol having a molecular weightof 500 to 1,000, diethyl ether of polypropylene glycol having amolecular weight of 1,000 to 1,500; and mono- and polycarboxylic estersthereof, for example, the acetic acid esters, mixed C₃ to C₈ fatty acidesters and C₁₃ Oxo acid diester of tetraethylene glycol.

Another suitable class of synthetic lubricating oils comprises theesters of dicarboxylic acids (e.g., phthalic acid, succinic acid, alkylsuccinic acids and alkenyl succinic acids, maleic acid, azelaic acid,suberic acid, sebasic acid, fumaric acid, adipic acid, linoleic aciddimer, malonic acid, alkylmalonic acids, alkenyl malonic acids) with avariety of alcohols (e.g., butyl alcohol, hexyl alcohol, dodecylalcohol, 2-ethylhexyl alcohol, ethylene glycol, diethylene glycolmonoether, propylene glycol). Specific examples of these esters includedibutyl adipate, di(2-ethylhexyl)sebacate, di-n-hexyl fumarate, dioctylsebacate, diisooctyl azelate, diisodecyl azelate, dioctyl phthalatedidecyl phthalate, dieicosyl sebacate, the 2-ethylhexyl diester oflinoleic acid dimer, and the complex ester formed by reacting 1 mole ofsebacic acid with 2 moles of tetraethylene glycol and 2 moles of2-ethylhexanoic acid.

Esters useful as synthetic oils also include those made from C₅ to C₁₂monocarboxylic acids and polyols and polyol ethers such as neopentylglycol, trimethylolpropane, pentaerythritol, dipentaerythritol andtripentaerythritol. Silicon-based oils such as the polyalkyl-,polyaryl-, polyalkoxy-, or polyaryloxysiloxane oils and silicate oilscomprise another useful class of synthetic lubricants; they includetetraethyl silicate, tetraisopropyl silicate,tetra-(2-ethylhexyl)silicate, tetra-(4-methyl-2-ethylhexyl)silicate,tetra-(p-tert-butylphenyl)silicate, hexa-(4-methyl-2-pentoxy)disiloxane, poly(methyl)siloxanes and poly(methyl-phenyl)siloxanes.Other synthetic lubricating oils include liquid esters ofphosphorus-containing acids (e.g., tricresyl phosphate, trioctylphosphate, diethyl ester of decylphosphonic acid) and polymerictetrahydrofurans.

Unrefined, refined and rerefined oils can be used in the lubricants ofthe present invention. Unrefined oils are those obtained directly from anatural or synthetic source without further purification treatment. Forexample, a shale oil obtained directly from retorting operations, apetroleum oil obtained directly from distillation or ester oil obtaineddirectly from an esterification process and used without furthertreatment would be an unrefined oil. Refined oils are similar to theunrefined oils except they have been further treated in one or morepurification steps to improve one or more properties. Many suchpurification techniques, such as distillation, solvent extraction, acidor base extraction, filtration and percolation are known to thoseskilled in the art. Rerefined oils are obtained by processes similar tothose used to obtain refined oils applied to refined oils which havebeen already used in service. Such rerefined oils are also known asreclaimed or reprocessed oils and often are additionally processed bytechniques for removal of spent additives and oil breakdown products.

Additional Formulation Components

As indicated above, the additives of the present invention may be mixedwith other types of additives selected to perform at least one desiredfunction. Typical of such formations are detergent/inhibitor, viscositymodification, wear inhibitor, oxidation inhibitor, corrosion inhibitor,friction modifier, foam inhibitor, rust inhibitor, demulsifier, lube oilflow improvers, and seal swell control. Each class of such additionaladditives is discussed in more detail below.

Detergent/Inhibitor

Metal-containing detergents which can also act as rust inhibitors hencethe term "detergent/inhibitor" or simply "DI", include the metal saltsof sulphonic acids, alkyl phenols, sulphurized alkyl phenols, alkylsalicylates, naphthenates, and other oil soluble mono- and dicarboxylicacids as well as metal-containing complexes thereof. Usually thesemetal-containing detergent/inhibitors are used in lubricating oil inamounts of about 0.01 to 10, e.g. 0.1 to 5 wt. %, based on the weight ofthe total lubricating composition. Marine diesel lubricating oilstypically employ such metal-containing rust inhibitors and detergents inamounts of up to about 20 wt. %.

Metal detergent/inhibitors are generally basic (viz, overbased) alkalior alkaline earth metal salts (or mixtures thereof, e.g. mixtures of Caand Mg salts) of one or more organic sulfonic acid (generally apetroleum sulfonic acid or a synthetically prepared alkaryl sulfonicacid), petroleum naphthenic acids, alkyl benzene sulfonic acids, alkylphenols, alkylene-bis-phenols, oil soluble fatty acids and the like,such as are described in U.S. Pat. Nos. 2,501,731; 2,616,904; 2,616,905;2,616,906; 2,616,911; 2,616,924; 2,616,925; 2,617,049; 2,777,874;3,027,325; 3,256,186; 3,282,835; 3,384,585; 3,373,108; 3,350,308;3,365,396; 3,342,733; 3,320,162; 3,312,618; 3,318,809 and 3,562,159, thedisclosures of which are herein incorporated by reference. Among thepetroleum sulfonates, the most useful products are those prepared by thesulfonation of suitable petroleum fractions with subsequent removal ofacid sludge and purification. Synthetic alkaryl sulfonic acids areusually prepared from alkylated benzenes such as the Friedel-Craftsreaction product of benzene and a polymer such as tetrapropylene, C₁₈ toC₂₄ hydrocarbon polymer, etc. Suitable acids may also be obtained bysulfonation of alkylated derivatives of such compounds as diphenyleneoxide thianthrene, phenolthioxine, diphenylene sulfide, phenothiazine,diphenyl oxide, diphenyl sulfide, diphenylamine, cyclohexane, decahydronaphthalene and the like.

The terms "basic salt" and "overbased salt" are used to designate metalsalts wherein the metal is present in stoichiometrically larger amountsthan the acid radical.

As used in this discussion, the term "complex" refers to basic metalsalts which contain metal in an amount in excess of that present in aneutral or normal metal salt. The "base number" of a complex is thenumber of milligrams of KOH to which one gram of the complex isequivalent as measured by titration.

The commonly employed methods for preparing the basic salts involveheating a mineral oil solution of the normal metal salt of the acid witha metal neutralizing agent. The use of a "promoter" in theneutralization step to aid the incorporation of a large excess of metalis known and is preferred for the preparation of such compositions.

Examples of compounds useful as the promoter include phenolic substancessuch as phenol, naphthol, alkyl phenols, thiophenol, sulfurized alkylphenols, and condensation products of formaldehyde with a phenolicsubstance; alcohols such as methanol, 2-propanol, octanol, cellosolve,carbitol, ethylene glycol, stearyl alcohol and cyclohexanol; and aminessuch as aniline, phenylene diamine, phenothiazine, phenolbeta-naphthylamine and dodecylamine.

The alkali and alkaline earth metal compounds which may be used inneutralizing these acids to provide the metal salts include the oxidesand hydroxides, alkoxides, carbonates, carboxylate, sulfide,hydrosulfide, nitrate, borates and ethers of magnesium, calcium, andbarium. Examples are calcium oxide, calcium hydroxide, magnesium acetateand magnesium borate. As noted, the alkaline earth metal compound isused in excess of that required to complete neutralization of thealkaryl sulfonic acids. Generally, the amount ranges from about 100 to220%, although it is preferred to use at least 125%, of thestoichiometric amount of metal required for complete neutralization.

Various other preparations of basic alkaline earth metal alkarylsulfonates are known, such as U.S. Pat. Nos. 3,150,088 and 3,150,089wherein overbasing is accomplished by hydrolysis of analkoxide-carbonate complex with the alkaryl sulfonate in a hydrocarbonsolvent-diluent oil.

An example of a convenient process for the preparation of themetal-containing complexes employs an oil-soluble sulfonic acid, such asa synthetically prepared didodecylbenzene sulfonic acid, which is mixedwith an excess of lime (e.g., 10 equivalents per equivalent of the acid)and a promoter such as methanol, heptylphenol, or mixture thereof, and asolvent such as mineral oil, at 50° C. to 150° C. and the process massis then carbonated until a homogeneous mass is obtained. Complexes ofsulfonic acids, carboxylic acids, and mixtures thereof are obtainable byprocesses such as are described in U.S. Pat. No. 3,312,618. Anotherexample is the preparation of a magnesium sulfonate normal magnesiumsalt thereof, an excess of magnesium oxide, water, and preferably alsoan alcohol such as methanol.

The carboxylic acids useful for preparing sulfonate carboxylatecomplexes, and carboxylate complexes, i.e., those obtainable fromprocesses such as the above wherein a mixture of sulfonic acid andcarboxylic acid or a carboxylic acid alone is used in lieu of thesulfonic acid, are oil-soluble acids and include primarily fatty acidswhich have at least about 12 aliphatic carbon atoms and not more thanabout 24 aliphatic carbon atoms. Examples of these acids include:palmitic, stearic, myristic, oleic, linoleic, dodecanoic, behenic, etc.Cyclic carboxylic acids may also be employed. These include aromatic andcycloaliphatic acids. The aromatic acids are those containing abenzenoid structure (i.e., benzene, naphthalene, etc.) and anoil-solubilizing radical or radicals having a total of at least about 15to 18 carbon atoms, preferably from about 15 to about 200 carbon atoms.Examples of the aromatic acids include: stearyl-benzoic acid, phenylstearic acid, mono- or polywax-substituted benzoic or naphthoic acidswherein the wax group consists of at least about 18 carbon atoms, cetylhydroxybenzoic acids, etc. The cycloaliphatic acids contemplated have atleast about 12, usually up to about 30 carbon atoms. Examples of suchacids are petroleum naphthenic acids, cetyl cyclohexane carboxylicacids, dilauryl decahydro naphthalene carboxylic acids, dioctylcyclopentane carboxylic acids, etc. The thiocarboxylic acid analogs ofthe above acids, wherein one or both of the oxygen atoms of the carboxylgroup are replaced by sulfur, are also contemplated.

The ratio of the sulfonic acid to the carboxylic acid in mixtures istypically at least 1:1 (on a chemical equivalent basis) and is usuallyless than 5:1, preferably from 1:1 to 2:1.

Usually, the basic composition obtained according to the above-describedmethod is treated with carbon dioxide until its total base number (TBN)is less than about 50, as determined by ASTM procedure D-2896. In manyinstances, it is advantageous to form the basic product by adding a Caor Mg base portionwise and carbonating after the addition of eachportion. Products with very high metal ratios (10 or above) can beobtained by this method. As used herein, the term "metal ratio" refersto the ratio of total equivalents of alkaline earth metal in thesulfonate complex to equivalents of sulfonic acid anion therein. Forexample, a normal sulfonate has a metal ratio of 1.0 and a calciumsulfonate complex containing twice as much calcium as the normal salthas a metal ratio of 2.0. The overbased metal detergent compositionsusually have metal ratios of at least about 1. 1, for example, fromabout 1.1 to about 30, with metal ratios of from about 2 to 20 beingpreferred.

Neutral metal sulfonates are frequently used as rust inhibitors.Polyvalent metal alkyl salicylate, naphthenate and phenate materials areknown additives for lubricating oil compositions to improve their hightemperature performance and to counteract deposition of carbonaceousmatter on pistons (U.S. Pat. No. 2,744,069). They can be methylenebridged or sulfur bridged.

The sulfurized metal phenates represent a preferred class of phenatesand can be considered the "metal salt of a phenol sulfide" which thusrefers to a metal salt whether neutral or basic. They can be typified bythe general formula: ##STR22## where x=1 or 2, n=0, 1 or 2; or apolymeric form of such a compound, where R is an alkyl radical, n and xare each integers from 1 to 4, and the average number of carbon atoms inall of the R groups is at least about 9 in order to ensure adequatesolubility in oil. The individual R groups may each contain from 5 to40, preferably 8 to 20, carbon atoms. The metal salt is prepared byreacting an alkyl phenol sulfide with a sufficient quantity of metalcontaining material to impart the desired alkalinity to the sulfurizedmetal phenate.

Regardless of the manner in which they are prepared, the sulfurizedalkyl phenols which are useful generally contain from about 2 to about14 wt. %, preferably about 4 to about 12 wt. % sulfur based on theweight of sulfurized alkyl phenol.

The sulfurized alkyl phenol may also be converted by reaction with ametal containing material including oxides, hydroxides and complexes inan amount sufficient to neutralize said phenol and, if desired, tooverbase the product to a desired alkalinity by procedures well known inthe art. Preferred is a process of neutralization utilizing a solutionof metal in a glycol ether.

The neutral or normal sulfurized metal phenates are those in which theratio of metal to phenol nucleus is about 1:2. The "overbased" or"basic" sulfurized metal phenates are sulfurized metal phenates whereinthe ratio of metal to phenol is greater than that of stoichiometric,e.g. basic sulfurized metal dodecyl phenate, has a metal content up toand greater than 100% in excess of the metal present in thecorresponding normal sulfurized metal phenates wherein the excess metalis produced in oil-soluble or dispersible form (as by reaction withCO₂).

Magnesium and calcium containing detergents although beneficial in otherrespects can increase the tendency of the lubricating oil to oxidize.This is especially true of the highly basic sulphonates.

The magnesium and/or calcium is generally present as basic or neutraldetergents such as the sulphonates and phenates.

Viscosity Modifiers

A viscosity index (VI) improver, also referred to as viscosity modifier,is typically employed in multi-grade automobile engine lubricating oils.Viscosity modifiers impart high and low temperature operability to thelubricating oil and permit it to remain relatively viscous at elevatedtemperatures and also exhibit acceptable viscosity or fluidity at lowtemperatures. Viscosity modifiers are generally high molecular weighthydrocarbon polymers including polyesters. The viscosity modifiers mayinclude derivatized polymers recited above which include variousproperties or functions, including dispersancy properties. These oilsoluble viscosity modifying polymers will generally have number averagemolecular weights of from 10³ to 10⁶, preferably 10⁴ to 10⁶, e.g.,20,000 to 250,000, as determined by gel permeation chromatography orosmometry.

Examples of suitable hydrocarbon polymers which can be used areviscosity improvers include homopolymers and copolymers of two or moremonomers of C₂ to C₃₀, e.g. C₂ to C₈ olefins, including both alphaolefins and internal olefins, which may be straight or branched,aliphatic, aromatic, alkyl-aromatic, cycloaliphatic, etc. Frequentlythey will be of ethylene with C₃ to C₃₀ olefins, particularly preferredbeing the copolymers of ethylene and propylene. Other polymers can beused such as polyisobutylenes, homopolymers and copolymers of C₆ andhigher alpha olefins, atactic polypropylene, hydrogenated polymers andcopolymers and terpolymers of styrene, e.g. with isoprene and/orbutadiene and hydrogenated derivatives thereof. The polymer may bedegraded in molecular weight, for example, by mastication, extrusion,oxidation or thermal degradation, and it may be oxidized and containoxygen. Also included are derivatized polymers such as post-graftedinterpolymers of ethylene-propylene with an active monomer such asmaleic anhydride which may be further reacted with an alcohol, or amine,e.g. an alkylene polyamine or hydroxy amine, e.g., see U.S. Pat. Nos.4,089,794: 4,160,739 and 4,137,185; or copolymers of ethylene andpropylene reacted or grafted with nitrogen compounds such as shown inU.S. Pat. Nos. 4,068,056; 4,068,058; 4,146,489 and 4,149,984.

Useful hydrocarbon polymers include ethylene copolymers containing from15 to 90 wt. % ethylene, preferably 30 to 80 wt. % of ethylene and 10 to85 wt. %, preferably 20 to 70 wt. % of one or more C₃ to C₂₈, preferablyC₃ to C₁₈, more preferably C₃ to C₈, alpha-olefins. While not essential,such copolymers preferably have a degree of crystallinity of less than25 wt. %, as determined by X-ray and differential scanning calorimetry.Copolymers of ethylene and propylene or ethylene and butene are mostpreferred. Other alpha-olefins suitable in place of propylene to formthe copolymer, or to be used in combination with ethylene and propylene,to form a terpolymer, tetrapolymer, etc., include 1-butene, 1-pentene,1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, etc.; also branchedchain alpha-olefins, such as 4-methyl-1-pentene, 4-methyl-1-hexene,5-methylpentene-1,4,4-dimethyl-1-pentene, and 6-methylheptene-1, etc.,and mixtures thereof.

Terpolymers, tetrapolymers, etc., of ethylene, said C₃ to C₂₈alpha-olefin, and a non-conjugated diolefin or mixtures of suchdiolefins may also be used. The amount of the non-conjugated diolefingenerally ranges from about 0.5 to 20 mole %, preferably from about 1 toabout 7 mole %, based on the total amount of ethylene and alpha-olefinpresent.

The polyester VI improvers are generally polymers of esters ofethylenically unsaturated C₃ to C₈ mono- and dicarboxylic acids such asmethacrylic and acrylic acids, maleic acid, maleic anhydride, fumaricacid, etc.

Examples of unsaturated esters that may be used include those ofaliphatic saturated mono alcohols of at least I carbon atom andpreferably of from 12 to 20 carbon atoms, such as decyl acrylate, laurylacrylate, stearyl acrylate, eicosanyl acrylate, docosanyl acrylate,decyl methacrylate, diamyl fumarate, lauryl methacrylate, cetylmethacrylate, stearyl methacrylate, and the like and mixtures thereof.

Other esters include the vinyl alcohol esters of C₂ to C₂₂ fatty or monocarboxylic acids, preferably saturated such as vinyl acetate, vinyllaurate, vinyl palmitate, vinyl stearate, vinyl oleate, and the like andmixtures thereof. Copolymers of vinyl alcohol esters with unsaturatedacid esters such as the copolymer of vinyl acetate with dialkylfumarates, can also be used.

The esters may be copolymerized with still other unsaturated monomerssuch as olefins, e.g. 0.2 to 5 moles of C₂ to C₂₀ aliphatic or aromaticolefin per mole of unsaturated ester, or per mole of unsaturated acid oranhydride followed by esterification. For example, copolymers or styrenewith maleic anhydride esterified with alcohols and amines are known,e.g., see U.S. Pat. No. 3,702,300.

Such ester polymers may be grafted with, or the ester copolymerizedwith, polymerizable unsaturated nitrogen-containing monomers to impartdispersancy to the VI improvers. Examples of suitable unsaturatednitrogen-containing monomers include those containing 4 to 20 carbonatoms such as amino substituted olefins asp-(beta-diethylaminoethyl)styrene; basic nitrogen-containingheterocycles carrying a polymerizable ethylenically unsaturatedsubstituent, e.g. the vinyl pyridines and the vinyl alkyl pyridines suchas 2-vinyl-5-ethyl pyridine, 2-methyl-5-vinyl pyridine,2-vinyl-pyridine, 4-vinylpyridine, 3-vinyl-pyridine,3-methyl-5-vinyl-pyridine, 4-methyl-2-vinyl-pyridine,4-ethyl-2-vinyl-pyridine and 2-butyl-1-5-vinyl-pyridine and the like.N-vinyl lactams are also suitable, e.g. N-vinyl pyrrolidones or N-vinylpiperidones. The vinyl pyrrolidones are preferred and are exemplified byN-vinyl pyrrolidone, N-(l -methylvinyl) pyrrolidone, N-vinyl-5-methylpyrrolidone, N-vinyl-3,3-dimethylpyrrolidone, N-vinyl-5-ethylpyrrolidone, etc.

Such nitrogen- and ester-containing polymeric viscosity index improverdispersants are generally employed in concentrations of from about 0.05to 10 wt. % in the fully formulated oil, and preferably from about 0.1to 5 wt. %, and more preferably from about 0.5 to 3 wt. % can reduce(e.g., to about 0.5 wt. %) the amount of the ashless dispersant employedto provide the required dispersancy to the oil formulation.

Antiwear Agents

Antiwear agents, as their name implies, reduce wear of moving metallicparts. Representative of conventional antiwear agents which may be usedinclude, for example, the zinc dialkyl dithiophosphates, and the zincdiaryl dithiophosphates.

Suitable phosphates include dihydrocarbyl dithiophosphates, wherein thehydrocarbyl groups contain an average of at least 3 carbon atoms.Particularly useful are metal salts of at least one dihydrocarbyldithiophosphoric acid wherein the hydrocarbyl groups contain an averageof at least 3 carbon atoms. The acids from which the dihydrocarbyldithiophosphates can be derived can be illustrated by acids of theformula: ##STR23## wherein R¹⁶ and R¹⁷ are the same or different and arealkyl, cycloalkyl, aralkyl, alkaryl or substituted substantiallyhydrocarbon radical derivatives of any of the above groups, and whereinthe R¹⁶ and R¹⁷ groups in the acid each have, on average, at least 3carbon atoms.

By "substantially hydrocarbon" is meant radicals containing substituentgroups (e.g., 1 to 4 substituent groups per radical moiety) such asether, ester, nitro or halogen which do not materially affect thehydrocarbon character of the radical.

Specific examples of suitable R¹⁶ and R¹⁷ radicals include isopropyl,isobutyl, n-butyl, sec-butyl, n-hexyl, heptyl, 2-ethylhexyl, diisobutyl,isooctyl, decyl, dodecyl, tetradecyl, hexadecyl, octadecyl,butylphenyl,o,p-depentylphenyl, octylphenyl, polyiso-butene-(molecularweight 350)-substituted phenyl, tetrapropylene-substituted phenyl,beta-octylbutyl-naphthyl, cyclopentyl, cyclohexyl, phenyl, chlorophenyl,o-dichlorophenyl, bromophenyl, naphthenyl, 2-methylcyclohexyl, benzyl,chlorobenzyl, chloropentyl, dichlorophenyl, nitrophenyl, dichlorodecyland xenyl radicals. Alkyl radicals having about 3 to 30 carbon atoms,and aryl radicals having about 6 to 30 carbon atoms, are preferred.Particularly preferred R¹⁶ and R¹⁷ radicals are alkyl of 4 to 18carbons.

The phosphorodithioic acids are readily obtainable by the reaction ofphosphorus pentasulfide and an alcohol or phenol. The reaction involvesmixing, at a temperature of about 20° C. to 200° C., 4 moles of thealcohol or phenol with one mole of phosphorus pentasulfide. Hydrogensulfide is liberated as the reaction takes place. Mixtures of alcohols,phenols or both can be employed, e.g., mixtures of C₃ to C₃₀ alkanols,C₆ to C₃₀ aromatic alcohols, etc. The metals useful to make thephosphate salts include Group I metals, Group II metals, aluminum, lead,tin, molybdenum, manganese, cobalt and nickel. Zinc is the preferredmetal. Examples of metal compounds which may be reacted with the acidinclude lithium oxide, lithium hydroxide, lithium carbonate, lithiumpentylate, sodium oxide, sodium hydroxide, sodium carbonate, sodiummethylate, sodium propylate, sodium phenoxide, potassium oxide,potassium hydroxide, potassium carbonate, potassium methylate, silveroxide, silver carbonate, magnesium oxide, magnesium hydroxide, magnesiumcarbonate, magnesium ethylate, magnesium propylate, magnesium phenoxide,calcium oxide, calcium hydroxide, calcium carbonate, calcium methylate,calcium propylate, calcium pentylate, zinc oxide, zinc hydroxide, zinccarbonate, zinc propylate, strontium oxide, strontium hydroxide, cadmiumoxide, cadmium hydroxide, cadmium carbonate, cadmium ethylate, bariumoxide, barium hydroxide, barium hydrate, barium carbonate, bariumethylate, barium pentylate, aluminum oxide, aluminum propylate, leadoxide, lead hydroxide, lead carbonate, tin oxide, tin butylate, cobaltoxide, cobalt hydroxide, cobalt carbonate, cobalt pentylate, nickeloxide, nickel hydroxide and nickel carbonate.

In some instances, the incorporation of certain ingredients,particularly carboxylic acids or metal carboxylates such as smallamounts of the metal acetate or acetic acid used in conjunction with themetal reactant will facilitate the reaction and result in an improvedproduct. For example, the use of up to about 5% of zinc acetate incombination with the required amount of zinc oxide facilitates theformation of a zinc phosphorodithioate.

The preparation of metal phosphorodithioates is well known in the artand is described in a large number of issued patents, including U.S.Pat. Nos. 3,293,181; 3,397,145; 3,396,109 and 3,442,804, the disclosuresof which are hereby incorporated by reference insofar as the preparationof metal salts of organic phosphorodithioic acids useful in thisinvention are described.

Also useful as antiwear additives are amine derivatives ofdithiophosphoric acid compounds, such as are described in U.S. Pat. No.3,637,499, the disclosure of which is hereby incorporated by referencein its entirety.

The zinc salts are most commonly used as antiwear additives inlubricating oil in amounts of 0.1 to 10, preferably 0.2 to 2 wt. %,based upon the total weight of the lubricating oil composition. They maybe prepared in accordance with known techniques by first forming adithiophosphoric acid, usually by reaction of an alcohol or a phenolwith P₂ S₅ and then neutralizing the dithiophosphoric acid with asuitable zinc compound.

Mixtures of alcohols may be used including mixtures of primary andsecondary alcohols, secondary generally for imparting improved antiwearproperties, and primary for thermal stability. Mixtures of the two areparticularly useful. In general, any basic or neutral zinc compoundcould be used but the oxides, hydroxides and carbonates are mostgenerally employed. Commercial additives frequently contain an excess ofzinc due to use of an excess of the basic zinc compound in theneutralization reaction.

The zinc dihydrocarbyl dithiophosphates are oil soluble salts ofdihydrocarbyl esters of dithiophosphoric acids and may be represented bythe following formula: ##STR24## wherein R¹⁶ and R¹⁷ are as described inconnection with the previous formula.

Suitable antiwear agents also comprise the phosphorous- andsulfur-containing product mixtures described in U.S. application Ser.No. 210,831 filed on Jun. 24, 1988 by Ryer and Gutierrez and theContinuation-in-Part thereof: U.S. Ser. No. 370,315, filed Jun. 22,1989, the disclosures thereof are incorporated herein by reference.

In a preferred embodiment of the phosphorous- and sulfur-containingproduct mixtures disclosed in said commonly assigned applications, thefollowing three components, namely: (1) organic phosphite ester, (2)hydrocarbyl thioalkanol, and (3) heterodialkanol are reacted inadmixture, preferably in simultaneous admixture.

Preferred hydrocarbyl thioalkanol reactants include C₈ to C₁₈thioethanols. The preferred heterodialkanols are thiodialkanols.Representative thiodialkanols include 2,2'-thiodiethanol;3,3'-thiodipropanol; thio-bis ethoxy-ethanol;thiobisisopropoxyisopropanol; and mixtures thereof.

Oxidation Inhibitors

Oxidation inhibitors reduce the tendency of mineral oils to deterioratein service, which deterioration can be evidenced by the products ofoxidation such as sludge and varnish-like deposits on the metal surfacesand by viscosity growth.

Useful antioxidant materials include oil soluble phenolic compounds, oilsoluble sulfurized organic compounds, oil soluble amine antioxidants,oil soluble organo borates, oil soluble organo phosphites, oil solubleorganophosphates, oil soluble organo dithiophosphates and mixturesthereof. Preferably such antioxidants are metal-free (that is, free ofmetals which are capable of generating sulfated ash), and therefore aremost preferably ashless (having a sulfated ash value of not greater than1 wt. % SASH, as determined by ASTMD874).

Illustrative of oil soluble phenolic compounds are alkylatedmonophenols, alkylated hydroquinones, hydroxylated thiodiphenyl ethers,alkylidenebis phenols, benzyl compounds, acylaminophenols, and estersand amides of hindered phenol-substituted alkanoic acids.

Examples of Phenolic Antioxidants

1. Alkylated monophenols 2,6-di-tert-butyl-4-methylphenol;2,6-di-tert-butylphenol; 2-tert-butyl-4,6 dimethylphenol;2,6-di-tertbutyl-4-ethylphenol; 2,6-ditert-butyl-4-ethylphenol;2,6-di-tert-butyl-4-n-butyl-phenol; 2,6-di-tertbutyl-4-isobutylphenol;2,6-dicyclo-pentyl-4-methylphenol;2-(alpha-methylcyclohexyl)-4,6-dimethylphenol;2,6-dioctadecyl-4-methylphenol; 2,4,6-tricyclohexylphenol;2,6-di-tert-butyl-4-methoxymethyl-phenol; o-tert-butylphenol.

2. Alkylated hydroquinones 2,6-di-tert-butyl-4-methoxyphenol;2,5-di-tertbutyl-hydroquinone; 2,5-di-tert-amylhydroquinone;2,6-di-phenyl-4-octadecyloxy-phenol.

3. Hydroxylated thiodiphenyl ethers2,2'-thiobis(6-tert-butyl-4-methylphenol); 2,2'-thiobis(4-octylphenol);4,4'-thiobis(6-tert-butyl-3-methylphenol);4,4'-thiobis(6-tert-butyl-2-methylphenol).

4. Alkylidenebisphenols 2,2'-methylenebis(6-tert-butyl-4-methylphenol);2,2'-methylenebis(6-tert-butyl-4-ethylphenol);2,2'-methylenebis[4-methyl-6-(alpha-methylcyclohexyl)-phenol);2,2'-methylenebis(4-methyl-6-cyclohexylphenol);2,2'-methylenebis(6-nonyl-4-methylphenol);2,2'-methylenebis(4,6-di-tert-butyl-phenol);2,2'-methylidenebis(4,6-di-tert-butylphenol);2,2'-ethylidenebis(6-tert-butyl-4-isobutylphenol);2,2'-methylenebis[6-alpha-methylbenzyl)-4-nonylphenol];2,2'-methylenebis[6-(alpha, alpha-dimethylbenzyl)-4-nonyl-phenol];4,4'-methylenebis(2,6-di-tert-butylphenol);4,4'-methylenebis(6-tert-butyl-2-methylphenol);1,1-bis-(5-tert-butyl-4-hydroxy-2-methylphenyl)butane;2,6-di(3-tert-butyl-5-methyl-2-hydroxybenzyl)-4-methylphenol;1,1,3-tris(5-tert-butyl-4-hydroxy-2-methylphenyl)-3-n-dodecylmercaptobutane; ethylene glycolbis[3,3-bis(3'-tert-butyl-4'-hydroxylphenyl)butyrate];di(3-tert-butyl-4-hydroxy-5-methylphenyl)dicyclopentadiene;di[2-(3'-tert-butyl-2'-hydroxy-5'-methylbenzyl)-6-tertbutyl-4-methylphenyl]terephthalate.

5. Benzyl compounds1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-2,4,6-trimethyl-benzene;di(3,5-di-tert-butyl-4-hydroxybenzyl)sulfide;3,5-di-tert-butyl-4-hydroxybenzylmercaptoacetic acid isooctyl ester;bis(4-tert-butyl-3-hydroxy-2,6-dimethyl-benzyl)dithio-terephthalate;1,3,5-tris(3,5-di-tertbutyl-4-hydroxy-benzyl)isocyanurate1,3,5-tris(4-tertbutyl-3-hydroxy-2,6-dimethylbenzyl)isocyanurate;3,5-di-tert-butyl-4-hydroxybenzylphosphonic acid dioctadecyl ester3,5-di-tert-butyl-4-hydroxybenzylphosphonic acid mono-ethyl estercalcium salt.

6. Acylaminophenols 4-hydroxylauric acid anilide; 4-hydroxystearic acidanilide;2,4-bis-octylmercapto-6-(3,5-di-tert-butyl-4-hydroxyaniline)-s-triazine;N-(3,5-di-tert-butyl-4-hydroxyphenyl)carbamic acid octyl ester.

7. Esters of beta-(3,5-di-tert-butyl-4-hydroxy-phenyl)propionic acidwith mono- or polyhydric alcohols, e.g. with methanol; octadecanol;1,6-hexanediol; neopentyl glycol; thiodiethylene glycol; diethyleneglycol; triethylene glycol; pentaerythritol;tris(hydroxy-ethyl)isocyanurate; and di(hydroxyethyl)oxalic aciddiamide.

8. Esters of beta-(5-tert-butyl-4-hydroxy-3-methylphenyl)propionic acidwith mono- or polyhydric alcohols, e.g. with methanol; octadecanol;1,6-hexanediol; neopentyl glycol; thiodiethylene glycol; diethyleneglycol; triethylene glycol; pentaerythritol;tris(hydroxyethyl)isocyanurate; and di(hydroxy-ethyl)oxalic aciddiamide.

9. Amides of beta -(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid,e.g.,N,N'-di(3,5-di-tert-butyl-4-hydroxyphenyl-proprionyl)hexamethylenediamine;N,N'-di(3,5-di-tert-butyl-4-hydroxyphenylpropionyl) trimethylenediamine;N,N'-di-(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hydrazine.

Oil soluble sulfurized organic compounds include those represented bythe formula: ##EQU6## wherein S represents sulfur, x₄ is a whole numberhaving a value of from 1 to about 10, and R¹⁸ and R¹⁹ may be the same ordifferent organic groups. The organic groups may be hydrocarbon groupsor substituted hydrocarbon groups containing alkyl, aryl, aralkyl,alkaryl, alkanoate, thiazole, imidazole, phosphorothionate,beta-ketoalkyl groups, etc. The substantially hydrocarbon groups maycontain other substituents such as halogen, amino, hydroxyl, mercapto,alkoxy, aryloxy, thio, nitro, sulfonic acid, carboxylic acid, carboxylicacid ester, etc.

Specific examples of types of sulfurized compositions which are useful.Oxidation inhibitors include aromatic, alkyl or alkenyl sulfides andpolysulfides, sulfurized olefins, sulfurized carboxylic acid esters,sulfurized ester olefins, sulfurized oil, and mixtures thereof. Thepreparation of such oil-soluble sulfurized compositions is described inthe art, and U.S. Pat. No. 4,612,129 is incorporated herein by referencein its entirety for its disclosure of such preparations; including thetype and amount of reactants and catalysts (or promoters), temperaturesand other process conditions, and product purification and recoverytechniques (e.g., decoloring, filtering, and other solids and impurityremoval steps). The sulfurized organic compounds may be aromatic andalkyl sulfides such as dibenzyl sulfide, dixylyl sulfide,dicetylsulfide, diparaffin wax sulfide and polysulfide, cracked waxoleum sulfides, etc.

Examples of dialkenyl sulfides are described in U.S. Pat. No. 2,446,072.Examples of sulfides of this type include6,6'-dithiobis(5-methyl-4-nonene), 2-butenyl monosulfide and disulfide,and 2-methyl-2-butenyl monosulfide and disulfide.

Representative sulfurized olefins include sulfurized olefins prepared bythe reaction of an olefin (preferably containing 3 to 6 carbon atoms) ora lower molecular weight polyolefin derived therefrom, with asulfur-containing compound such as sulfur, sulfur monochloride and/orsulfur dichloride, hydrogen sulfide, etc. Isobutene, propylene and theirdimers, trimers and tetramers, and mixtures thereof are especiallypreferred olefinic compounds. Of these compounds, isobutylene anddiisobutylene are particularly desirable because of their availabilityand the particularly high sulfur-containing compositions which can beprepared therefrom.

The sulfurized organic compounds may be sulfurized oils which may beprepared by treating natural or synthetic oils including mineral oils,lard oil, carboxylic acid esters derived from aliphatic alcohols andfatty acids or aliphatic carboxylic acids (e.g., myristyl oleate andoleyl oleate) sperm whale oil and synthetic sperm whale oil substitutesand synthetic unsaturated esters or glycerides.

The sulfurized fatty acid esters can be prepared by reacting sulfur,sulfur monochloride, and/or sulfur dichloride with an unsaturated fattyester at elevated temperatures. Typical esters include C₁ to C₂₀ alkylesters of C₈ to C₂₄ unsaturated fatty acids such as palmitoleic, oleic,ricinoleic, petroselic, vaccenic, linoleic, linolenic, oleostearic,licanic, etc. Sulfurized fatty acid esters prepared from mixedunsaturated fatty acid esters such as are obtained from animal fats andvegetable oils such as tall oil, linseed oil, olive oil, castor oil,peanut oil, rape oil, fish oil, sperm oil, etc. also are useful.Specific examples of the fatty esters which can be sulfurized includelauryl talate, methyl oleate, ethyl oleate, lauryl oleate, cetyl oleate,cetyl linoleate, lauryl ricinoleate, oleolinoleate, oleostearate, andalkyl glycerides.

Another class of organic sulfur-containing compounds includes sulfurizedaliphatic esters of an olefinic monodicarboxylic acid. For example,aliphatic alcohols of from 1 to 30 carbon atoms can be used to esterifymonocarboxylic acids such as acrylic acid, methacrylic acid,2,4-pentadienic acid, etc. or fumaric acid, maleic acid, muconic acid,etc. Sulfurization of these esters is conducted with elemental sulfur,sulfur monochloride and/or sulfur dichloride.

Another class of sulfurized organic compounds include diester sulfides.Typical diesters include the butyl, amyl, hexyl, heptyl, octyl, nonyl,decyl, tridecyl, myristyl, pentadecyl, cetyl, heptadecyl, stearyl,lauryl, andeicosyl; diesters of thiodialkanoic acids such as propionic,butanoic, pentanoic and hexanoic acids. Of the diester sulfides, aspecific example is dilauryl,3,3'-thiodipropionate.

Other suitable sulfurized organic compound antioxidants include thosederived from a particular type of cyclic or bicyclic olefin which is aDiels-Alder adduct of at least one dienophile with at least onealiphatic conjugated diene. The sulfurized Diels-Alder adducts can beprepared by reacting various sulfurizing agents with the Diels-Alderadducts as described more fully below. Typically, the sulfurizing agentis sulfur.

The Diels-Alder adducts are a well-known, art-recognized class ofcompounds prepared by the diene synthesis of Diels-Alder reaction. Asummary of the prior art relating to this class of compounds is found inthe Russian monograph, "Dienovyi Sintes", Izdatelstwo Akademii NaukSSSR, 1963 by A. S. Onischenko. (Translated into the English language byL. Mandel as A. S. Onischenko, "Diene Synthesis", N.Y., Daniel Davey andCo., Inc., 1964). This monograph and references cited therein areincorporated by reference into the present specification.

Still further sulfurized organic compounds include at least onesulfurized terpene compound or a composition prepared by sulfurizing amixture comprising at least one terpene and at least one other olefiniccompound.

The term "terpene compound" as used in the specification and claims isintended to include the various isomeric terpene hydrocarbons having theempirical formula C₁₀ H₁₆, such as contained in turpentine, pine oil anddipentenes, and the various synthetic and naturally occurringoxygen-containing derivatives. Mixtures of these various compoundsgenerally will be utilized, especially when natural products such aspine oil and turpentine are used. Pine oil, for example, which isobtained by destructive distillation of waste pinewood with super-heatedsteam comprises a mixture of terpene derivatives such asalpha-terpineol, beta-terpineol, alpha-fenchol, camphor,bomeol/isobomeol, fenchone, estragole, dihydro alpha- terpineol,anethole, and other monoterpene hydrocarbons. The specific ratios andamounts of the various components in a given pine oil will depend uponthe particular source and the degree of purification. A group of pineoil-derived products are available commercially from HerculesIncorporated. The pine oil products generally known as terpene alcoholsavailable from Hercules Incorporated are particularly useful in thepreparation of this class of sulfurized products. Examples of suchproducts include alpha-Terpineol containing about 95 to 97% ofalpha-terpineol, a high purity tertiary terpene alcohol mixturetypically containing 96.3% of tertiary alcohols; Terpineol 318 Primewhich is a mixture of isomeric terpineols obtained by dehydration ofterpene hydrate and contains about 60 to 65 wt. % of alpha-terpineol and15 to 20% beta-terpineol, and 18 to 20% of other tertiary terpenealcohols. Other mixtures and grades of useful pine oil products also areavailable from Hercules under such designations as Yarmor 302, Hercopine oil, Yarmor 302W, Yarmor F and Yarmor 60.

The above terpene compounds may be sulfurized terpene compounds,sulfurized mixtures of terpene compounds or mixtures of at least oneterpene compound and at least one sulfurized terpene compound.Sulfurized terpene compounds can be prepared by sulfurizing terpenecompounds with sulfur, sulfur halides, or mixtures of sulfur dioxidewith hydrogen sulfide. Also, the sulfurization of various terpenecompounds has been described in the prior art. For example, thesulfurization of pine oil is described in U.S. Pat. No. 2,012,446.

The other olefinic compound which may be combined with the terpenecompound and sulfurized may be any of several olefinic compounds such asthose described earlier.

The other olefin used in combination with the terpene also may be anunsaturated fatty acid, an unsaturated fatty acid ester, mixturesthereof, or mixtures thereof with the olefins described above. The term"fatty acid" as used herein refers to acids which may be obtained byhydrolysis of naturally occurring vegetable or animal fats or oils.These fatty acids usually contain from 16 to 20 carbon atoms and aremixtures of saturated and unsaturated fatty acids. The unsaturated fattyacids generally contained in the naturally occurring vegetable or animalfats and oils may contain one or more double bonds and such acidsinclude palmitoleic acid, oleic acid, linoleic acid, linolenic acid, anderucic acid. The unsaturated fatty acids may comprise mixtures of acidssuch as those obtained from naturally occurring animal and vegetableoils such as lard oil, tall oil, peanut oil, soybean oil, cottonseedoil, sunflower seed oil, or wheat germ oil. Tall oil is a mixture ofrosin acids, mainly abietic acid, and unsaturated fatty acids, mainlyoleic and linoleic acids. Tall oil is a by-product of the sulfateprocess for the manufacture of wood pulp.

The most particularly preferred unsaturated fatty acid esters are thefatty oils, that is, naturally occurring esters of glycerol with thefatty acids described above, and synthetic esters of similar structure.Examples of naturally occurring fats and oils containing unsaturationinclude animal fats such as Neat's foot oil, lard oil, depot fat, beeftallow, etc. Examples of naturally occurring vegetable oils includecottonseed oil, corn oil, poppyseed oil, safflower oil, sesame oil,soybean oil, sunflower seed oil and wheat germ oil.

The fatty acid esters which are useful also may be prepared fromaliphatic olefinic acids of the type described above such as oleic acid,linoleic acid, linolenic acid, and behenic acid by reaction withalcohols and polyols. Examples of aliphatic alcohols which may bereacted with the above-identified acids include monohydric alcohols suchas methanol, ethanol, n-propanol, isopropanol, the butanols, etc.; andpolyhydric alcohols including ethylene glycol, propylene glycol,trimethylene glycol, neopentyl glycol, glycerol, etc.

The sulfurized derivatives of the other olefin compounds can be preparedby methods known in the art utilizing sulfurizing reagents such assulfur, sulfur halides or mixtures of sulfur or sulfur dioxide withhydrogen sulfide.

Exemplary of amine antioxidants are phenyl-substituted andphenylene-substituted amines, N-nitro phenylhydroxylamine, isoindolinecompounds, phosphinodithioic acid-vinyl carboxylate adducts,phosphorodithioate ester-aldehyde reaction products,phosphorodithioate-alkylene oxide reaction products, silyl esters ofterephthalic acid, bis-1,3-alkylamino-2-propanol, anthranilamidecompounds, anthranilic acid esters, alpha-methyl styrenated aromaticamines, aromatic amines and substituted benzophenones, aminoguanidines,peroxide-treated phenothiazine, N-substituted phenothiazines andtriazines, 3-tertiary alkyl-substituted phenothiazines, alkylateddiphenyl-amines, 4-alkylphenyl-1-alkyl-2-naphthylamines, di-benzazepinecompounds, fluorinated aromatic amines, alkylated polyhydroxy benzenoidcompounds, substituted indans, dimethyl octadecylphosphonate-aryliminodi-alkanol copolymers and substituted benzo-diazoborole.

Examples of Amine Antioxidants

N,N'-diisopropyl-p-phenylenediamine;N,N'-di-sec-butyl-p-phenylenediamine;N,N'-bis(1,4-dimethylpentyl)-p-phenylenediamine;N,N'-bis(1-ethyl-3-methylpentyl)-p-phenylenediamine;N,N'-bis(1-methylheptyl)-p-phenyl-enediamine;N,N'-diphenyl-p-phenylenediamine;N,N'-di-(naphthyl-2)-p-phenylenediamine;N-isopropyl-N'-phenyl-p-phenylenediamine;N-(1,3-dimethylbutyl)-N'-phenyl-n-phenylenediamine;N-(1-methylheptyl)-N'-phenyl-p-phenylenediamine;N-cyclohexyl-N'-phenyl-p-phenyl-enediamine;4-(p-toluenesulfonamido)diphenylamine;N,N'-dimethyl-N,N'-di-sec-butyl-p-phenylenediamine diphenyl-amine;4-isopropoxydiphenylamine; N-phenyl-1-naphthylamine;N-phenyl-2-naphthylamine; octylated diphenylamine; 4-n-butylaminophenol;4-butyryl-aminophenol; 4-nonanoylaminophenol; 4-dodecanoyl-aminophenol;4-octadecanoylaminophenol; di-(4-methoxyphenyl)amine;di-tert-butyl-4-dimethylaminomethylphenol; 2,4'-diaminodiphenylmethane;4,4'-diaminophenylmethane;N,N,N',N'-tetramethyl-4,4'-diaminodiphenylmethane;1,2-di[(2-methylphenyl)amino]ethane; 1,2-di(phenylamino)-propane;(o-tolyl)biguanide; di[4-(1',3'-dimethylbutyl)phenyl]amine;tert-octylated N-phenyl-1-napthyl-amino; and mixture of mono- anddialkylated tert-butyl-tert-octyldiphenylamines.

Oil soluble organo-borate, phosphate and phosphite antioxidants includealkyl- and aryl- (and mixed alkyl, aryl) substituted borates, alkyl- andaryl- (and mixed alkyl, aryl) substituted phosphates, alkyl- and aryl-(and mixed alkyl, aryl) substituted phosphites, and alkyl- and aryl-(and mixed alkyl, aryl) substituted dithiophosphates such asO,O,S-trialkyl dithiophosphates, O,O,S-triaryldithiophosphates anddithiophosphates having mixed substitution by alkyl andaryl groups,phosphorothionyl sulfide, phosphorus-containing silane, polyphenylenesulfide, amine salts of phosphinic acid and quinone phosphates.

A preferred class of antioxidants includes the sulfurizedalkyl-substituted hydroxyaromatic compounds. Sulfurizedalkyl-substituted hydroxyaromatic compounds and the methods of preparingthem are known in the art and are disclosed, for example, in thefollowing U.S. Patents (which are incorporated by reference herein):U.S. Pat. Nos. 2,139,766; 2,198,828; 2,230,542; 2,836,565; 3,285,854;3,538,166; 3,844,956; 3,951,830 and 4,115,287.

In general, the sulfurized alkyl-substituted hydroxyaromatic compoundsmay be prepared by reacting an alkyl-substituted hydroxyaromaticcompound with a sulfurizing agent such as elemental sulfur, a sulfurhalide (e.g., sulfurmonochloride or sulfur dichloride), a mixture ofhydrogen sulfide and sulfur dioxide, or the like. The preferredsulfurizing agents are sulfur and the sulfur halides, and especially thesulfur chlorides, with sulfur dichloride (SCl₂)being especiallypreferred.

The alkyl-substituted hydroxyaromatic compounds which are sulfurized toproduce antioxidant are generally compounds containing at least onehydroxy group (e.g., from 1 to 3 hydroxy groups) and at least one alkylradical (e.g., from 1 to 3 alkyl radicals) attached to the same aromaticring. The alkyl radical ordinarily contains about 3 to 100, andpreferably about 6 to 20, carbon atoms. The alkyl-substituted hydroxyaromatic compound may contain more than one hydroxy group as exemplifiedby alkyl resorcinols, hydroquinones and catechols, or it may containmore than one alkyl radical; but normally it contains only one of each.Compounds in which the alkyl and hydroxy groups are ortho, meta and parato each other, and mixtures of such compounds, are within the scope ofthe invention. Illustrative alkyl-substituted hydroxyaromatic compoundsare n-propylphenol, isopropylphenol, n-butylphenol, t-butylphenol,hexylphenol, heptylphenol, octylphenol, nonylphenol, n-dodecylphenol,(propenetetramer)-substituted phenol, octadecylphenol, eicosylphenol,polybutene (molecular weight about 1000)-substituted phenol,n-dodecylresorcinol and 2,4-di-t-butylphenol, and the alkyl-substitutedcatechols corresponding to the foregoing. Also included aremethylene-bridged alkyl-substituted hydroxyaromatic compounds of thetype which may be prepared by the reaction of an alkyl-substitutedhydroxyaromatic compound with formaldehyde or a formaldehyde-yieldingreagent such as trioxane or paraformaldehyde.

The sulfurized alkyl-substituted hydroxy-aromatic compound is typicallyprepared by reacting the alkyl-substituted hydroxyaromatic compound withthe sulfurizing agent at a temperature within the range of about 100° C.to 250° C. The reaction may take place in a substantially inert diluentsuch as toluene, xylene, petroleum naphtha, mineral oil, Cellosolve orthe like. If the sulfurizing agent is a sulfur halide, and especially ifno diluent is used, it is frequently preferred to remove acidicmaterials such as hydrogen halides by vacuum stripping the reactionmixture or blowing it with an inert gas such as nitrogen. If thesulfurizing agent is sulfur, it is frequently advantageous to blow thesulfurized product with an inert gas such as nitrogen or air so as toremove sulfur oxides and the like.

Also useful herein are antioxidants disclosed in the following U.S.Patents, the disclosures of which are herein incorporated by referencein their entirety: U.S. Pat. Nos. 3,451,166; 3,458,495; 3,470,099;3,511,780; 3,687,848; 3,770,854; 3,850,822; 3,876,733; 3,929,654;4,115,287; 4,136,041; 4,153,562; 4,367,152 and 4,737,301.

The most preferred antioxidants include oil soluble copper compounds.The copper may be blended into the oil as any suitable oil solublecopper compound. By oil soluble we mean the compound is oil solubleunder normal blending conditions in the oil or additive package. Thecopper compound may be in the cuprous or cupric form. The copper may bein the form of the copper dihydrocarbyl thio- or dithiophosphateswherein copper may be substituted for zinc in the compounds andreactions described above although 1 mole of cuprous or cupric oxide maybe reacted with 1 or 2 moles of the dithiophosphoric acid, respectively.Alternatively, the copper may be added as the copper salt of a syntheticor natural carboxylic acid. Examples include C₁₀ to C₁₈ fatty acids suchas stearic or palmitic, but unsaturated acids such as oleic or branchedcarboxylic acids such as napthenic acids of molecular weight from 200 to500 or synthetic carboxylic acids are preferred because of the improvedhandling and solubility properties of the resulting copper carboxylates.Also useful are oil soluble copper dithiocarbamates of the generalformula (RR'NCSS)_(n) Cu, where n is 1 or 2 and R and R' are the same ordifferent hydrocarbyl radicals containing from 1 to 18 and preferably 2to 12 carbon atoms and including radicals such as alkyl, alkenyl, aryl,aralkyl, alkaryl and cycloaliphatic radicals. Particularly preferred asR and R' groups are alkyl groups of 2 to 8 carbon atoms. Thus, theradicals may, for example, be ethyl, n-propyl, i-propyl, n-butyl,i-butyl, sec-butyl, amyl, n-hexyl, i-hexyl, n-heptyl, n-octyl, decyl,dodecyl, octadecyl, 2-ethylhexyl, phenyl, butylphenyl, cyclohexyl,methylcyclopentyl, propenyl, butenyl, etc. In order to obtain oilsolubility, the total number of carbon atoms (i.e., R and R') willgenerally be about 5 or greater. Copper sulphonates, phenates, andacetylacetonates may also be used.

Exemplary of useful copper compound antioxidants are copper (Cu^(I)and/or Cu^(II)) salts of alkenyl carboxylic acids or anhydrides such assuccinic acids or anhydrides. The salts themselves may be basic, neutralor acidic. They may be formed by reacting (a) any of the functionalizedpolymers which are useful as dispersants section, which have at leastone free carboxylic acid (or anhydride) group with (b) a reactive metalcompound. Suitable acid (or anhydride) reactive metal compounds includethose such as cupric or cuprous hydroxides, oxides, acetates, borates,and carbonates or basic copper carbonate.

Examples of the metal salts are Cu salts of poly-n-butene succinicanhydride (hereinafter referred to as Cu-PNBSA) polyisobutenyl succinicanhydride (hereinafter referred to as Cu-PIBSA), and Cu salts ofpoly-n-butene or polyisobutenyl succinic acid. Preferably, the selectedmetal employed is its divalent form, e.g., Cu+². The preferredsubstrates are polyalkenyl carboxylic acids in which the alkenyl grouphas a molecular weight greater than about 700. The alkenyl groupdesirably has a °₋₋ Mn from about 900 to 1,500, and up to 5,000. Thesematerials can be dissolved in a solvent, such as a mineral oil, andheated in the presence of a water solution (or slurry) of the metalbearing material. Heating may take place between 70° C. and about 200°C. Temperatures of 110° C. to 1 40° C. are entirely adequate. It may benecessary, depending upon the salt produced, not to allow the reactionto remain at a temperature above about 140° C. for an extended period oftime, e.g., longer than 5 hrs., or decomposition of the salt may occur.

The copper antioxidants (e.g., Cu-PIBSA, Cu-PNB, Cu-oleate, or mixturesthereof) will be generally employed in an amount of from about 50 to 500ppm by weight of the metal, in the final lubricating or fuelcomposition.

The copper antioxidants are inexpensive and are effective at lowconcentrations and therefore do not add substantially to the cost of theproduct. The results obtained are frequently better than those obtainedwith previously used antioxidants, which are expensive and used inhigher concentrations. In the amounts employed, the copper compounds donot interfere with the performance of other components of thelubricating composition, in many instances, completely satisfactoryresults are obtained when the copper compound is the sole antioxidant inaddition to the ZDDP. The copper compounds can be utilized to replacepart or all of the need for supplementary antioxidants. Thus, forparticularly severe conditions it may be desirable to include asupplementary, conventional antioxidant. However, the amounts ofsupplementary antioxidant required are small, far less than the amountrequired in the absence of the copper compound.

While any effective amount of the copper antioxidant can be incorporatedinto the lubricating oil composition, it is contemplated that sucheffective amounts be sufficient to provide said lube oil compositionwith an amount of the copper antioxidant of from about 5 to 500 (morepreferably 10 to 200, still more preferably 10 to 180, and mostpreferably 20 to 130 (e.g., 90 to 120)) ppm of added copper based on theweight of the lubricating oil composition. Of course, the preferredamount may depend, amongst other factors, on the quality of thebasestock lubricating oil.

Corrosion Inhibitors

Corrosion inhibitors, also known as anti-corrosive agents, reduce thedegradation of the metallic parts contacted by the lubricating oilcomposition. Illustrative of corrosion inhibitors are phosphosulfurizedhydrocarbons and the products obtained by reaction of aphosphosulfurized hydrocarbon with an alkaline earth metal oxide orhydroxide, preferably in the presence of an alkylated phenol or of analkylphenol thioester, and also preferably in the presence of carbondioxide. Phosphosulfirized hydrocarbons are prepared by reacting asuitable hydrocarbon such as a terpene, a heavy petroleum fraction of aC₂ to C₆ olefin polymer such as polyisobutylene, with from 5 to 30 wt. %of a sulfide of phosphorus for 1/2 to 15 hrs., at a temperature in therange of 65° C. to 315° C. Neutralization of the phosphosulfurizedhydrocarbon may be effected in the manner taught in U.S. Pat. No.2,969,324.

Other suitable corrosion inhibitors include copper corrosion inhibitorscomprising hydrocarbyl-thio-distributed derivatives of1,3,4-thiadiazole, e.g., C₂ to C₃₀ ; alkyl, aryl, cycloalkyl, aralkyland alkaryl-mono-, di-, tri-, tetra- or thio-substituted derivativesthereof.

Representative examples of such materials included2,5-bis(octylthio)-1,3,4-thiadiazole;2,5-bis(octyl-dithio)-1,3,4-thiadiazole;2,5-bis(octyltrithio)-1,3,4-thiadiazole;2,5-bis(octyltetrithio)-1,3,4-thiadiazole;2,5-bis(nonylthio)-1,3,4-thiadiazole;2,5-bis(dodecyl-dithio)-1,3,4-thiadiazole;2-dodecyldithio-5-phenyl-dithio-1,3,4-thiadiazole; 2,5-bis(cyclohexyldithio)-1,3,4-thiadiazole; and mixtures thereof.

Preferred copper corrosion inhibitors are the derivative of-1,3,4-thiadiazoles such as those described in U.S. Pat. Nos. 2,719,125,2,719,126 and 3,087,932; especially preferred is the compound2,5-bis(t-octyldithio)-1,3,4-thiadiazole commercially available as Amoco150, and 2,5-bis(t-nonyldithio)-1,3,4-thiadiazole, commerciallyavailable as Amoco 158.

The preparation of such materials is further described in U.S. Pat. Nos.2,719,125, 2,719,126, 3,087,932 and 4,410,436, the disclosures of whichare hereby incorporated by reference.

Corrosion inhibitors also include copper lead bearing corrosioninhibitors. Typically such compounds are the thiadiazole polysulphidescontaining from 5 to 50 carbon atoms, their derivatives and polymersthereof. Preferred materials are the derivatives of 1,3,4-thiadiazolessuch as those described in U.S. Pat. Nos. 2,719,125; 2,719,126 and3,087,932; especially preferred is the compound 2,5bis(t-octadithio)-1,3,4-thiadiazole, commercially available as Amoco150. Other similar materials also suitable are described in U.S. Pat.Nos. 3,821,236; 3,904,537; 4,097,387; 4,107,059; 4,136,043; 4,188,299and 4,193,882.

Other suitable corrosion inhibitors are the thio and polythiosulphenamides of thiadiazoles such as those described in U.K. PatentSpecification 1,560,830. These compounds can be included in thelubricating composition in an amount from 0.01 to 10, preferably 0.1 to5.0 wt. % based on the weight of the composition.

Friction Modifiers

Friction modifiers serve to impart the proper friction characteristicsto lubricating oil compositions such as automatic transmission fluids.Representative examples of suitable friction modifiers are found in U.S.Pat. No. 3,933,659 which discloses fatty acid esters and amides; U.S.Pat. No. 4,176,074 which describes molybdenum complexes ofpolyisobutenyl succinic anhydride-amino alkanols; U.S. Pat. No.4,105,571 which discloses glycerol esters of dimerized fatty acids; U.S.Pat. No. 3,779,928 which discloses alkane phosphonic acid salts; U.S.Pat. No. 3,778,375 which discloses reaction products of a phosphonatewith an oleamide; U.S. Pat. No. 3,852,205 which discloses S-carboxy-alkylene hydrocarbyl succinimide, S-carboxy alkylene hydrocarbylsuccinamic acid and mixtures thereof; U.S. Pat. No. 3,879,306 whichdiscloses N-(hydroxyalkyl) alkenyl-succinamic acids or succinimides;U.S. Pat. No. 3,932,290 which discloses reaction products of di-(loweralkyl) phosphites and epoxides; and U.S. Pat. No. 4,028,258 whichdiscloses the alkylene oxide adduct of phosphosulfurizedN-(hydroxyalkyl) alkenyl succinimides. The disclosures of the abovereferences are herein incorporated by reference. Preferred frictionmodifiers are include hydroxy amines, as disclosed in U.S. Pat. No.5,078,893 and the thioether hydroxyamines as disclosed in U.S. Ser. No.211,428 filed Jun. 24, 1988; glycerol mono and dioleates; succinateesters, or metal salts thereof, of hydrocarbyl substituted succinicacids or anhydrides and thiobis alkanols such as described in U.S. Pat.No. 4,344,853 and amide friction modifiers such as the reaction productof isostearic acid and tetraethylene pentamine as disclosed in U.S. Ser.No. 425,939, filed Oct. 24, 1989 (our file PTF-048), all of which areherein incorporated by reference.

Anti-Foamants

Foam control can be provided by an antifoamant of the polysiloxane type,e.g. silicone oil and polydimethyl siloxane.

Rust Inhibitors

Organic, oil-soluble compounds useful as rust inhibitors comprisenonionic surfactants such as polyoxyalkylene polyols and esters thereof,and anionic surfactants such as salts of alkyl sulfonic acids. Suchanti-rust compounds are known and can be made by conventional means.Nonionic surfactants, useful as anti-rust additives in oleaginouscompositions usually owe their surfactant properties to a number of weakstabilizing groups such as ether linkages. Nonionic anti-rust agentscontaining ether linkages can be made by alkoxylating organic substratescontaining active hydrogens with an excess of the lower alkylene oxides(such as ethylene and propylene oxides) until the desired number ofalkoxy groups have been placed in the molecule.

The preferred rust inhibitors are polyoxyalkylene polyols andderivatives thereof. This class of materials are commercially availablefrom various sources: Pluronic Polyols from Wyandotte ChemicalsCorporation; Polyglycol 112-2, a liquid triol derived from ethyleneoxide and propylene oxide available from Dow Chemical Co.; and Tergitol,dodecylphenyl or monophenyl polyethylene glycol ethers, and Ucon,polyalkylene glycols and derivatives, both available from Union CarbideCorp. These are but a few of the commercial products suitable as rustinhibitors.

In addition to the polyols per se, the esters thereof obtained byreacting the polyols with various carboxylic acids are also suitable.Acids useful in preparing these esters are lauric acid, stearic acid,succinic acid, and alkyl- or alkenyl-substituted succinic acids whereinthe alkyl or alkenyl group contains up to about 20 carbon atoms.

The preferred polyols are prepared as block polymers. Thus, ahydroxy-substituted compound, R--(OH)n (wherein n is 1 to 6, and R isthe residue of a mono- or polyhydric alcohol, phenol, naphthol, etc.) isreacted with propylene oxide to form a hydrophobic base. This base isthen reacted with ethylene oxide to provide a hydrophylic portionresulting in a molecule having both hydrophobic and hydrophylicportions. The relative sizes of these portions can be adjusted byregulating the ratio of reactants, time of reaction, etc., as is obviousto those skilled in the art. Typically, the ethylene oxide units willcomprise from about 10 to about 40%, preferably from about 10 to about15% by wt. of the moleucle. Number average molecular weight of thepolyol is from about 2,500 to 4,500. The polyols having a moleculeweight of about 4,000 with about 10% attributable to ethylene oxideunits are particularly good.

Thus it is within the skill of the art to prepare polyols whosemolecules are characterized by hydrophobic and hydrophylic moietieswhich are present in a ratio rendering rust inhibitors suitable for usein any lubricant composition regardless of differences in the base oilsand the presence of other additives.

If more oil-solubility is needed in a given lubricating composition, thehydrophobic portion can be increased and/or the hydrophylic portiondecreased. If greater oil-in-water emulsion breaking ability isrequired, the hydrophylic and/or hydrophobic portions can be adjusted toaccomplish this.

Compounds illustrative of R--(OH)n include alkylene polyols such as thealkylene glycols, alkylene triols, alkylene tetrols, etc., such asethylene glycol, propylene glycol, glycerol, pentaerythritol, sorbitol,mannitol, and the like. Aromatic hydroxy compounds such as alkylatedmono- and polyhydric phenols and naphthols can also be used, e.g.,heptylphenol, dodecylphenol, etc.

Also useful rust inhibitors are alkoxylated fatty amines, amides,alcohols and the like, including such alkoxylated fatty acid derivativestreated with C₉ to C₁₆ alkyl-substituted phenols (such as the mono- anddi-heptyl, octyl, nonyl, decyl, undecyl, dodecyl and tridecyl phenols),as described in U.S. Pat. No. 3,849,501, which is also herebyincorporated by reference in its entirety.

Demulsifiers

Suitable demulsifiers include the esters disclosed in U.S. Pat. Nos.3,098,827 and 2,674,619 herein incorporated by reference.

Lube Oil Flow Improvers

Lubricating oil flow improvers (LOFI) include all those additives whichmodify the size, number, and growth of wax crystals in lube oils orfuels in such a way as to impart improved low temperature handling,pumpability, and/or vehicle operability as measured by such tests aspour point and mini rotary viscometry (MRV). The majority of flowimprovers are or contain either the backbone or sidechain type ofpolymers earlier described in the section entitled "Background Of TheInvention. " As noted there, representative of the sidechain LOFI's aredialkyl fumarate-vinyl acetate copolymers. Dialkyl fumarate-vinylacetate copolymers useful as LOFI's are described in U.S. Pat. No.4,839,074, the disclosure of which is incorporated herein by reference.

Seal Swell Agents

Seal swellants include mineral oils of the type that provoke swelling ofengine seals, including aliphatic alcohols of 8 to 13 carbon atoms suchas tridecyl alcohol, with a preferred seal swellant being characterizedas an oil-soluble, saturated, aliphatic or aromatic hydrocarbon ester offrom 10 to 60 carbon atoms and 2 to 4 linkages, e.g., dihexyl phthalate,as are described in U.S. Pat. No. 3,974,081.

Some of the above numerous additives can provide a multiplicity ofeffects e.g., a dispersant oxidation inhibitor. This approach is wellknown and need not be further elaborated herein.

Compositions, when containing these additives, typically are blendedinto the base oil in amounts which are effective to provide their normalattendant function. Representative effective amounts of such additivesare illustrated as follows:

    ______________________________________                                                          (Broad)    (Preferred)                                      Compositions      Wt. %      Wt. %                                            ______________________________________                                        V.I. Improver        1-12       1-4                                           Corrosion Inhibitor                                                                              0.01-3     0.01-1.5                                        Oxidation Inhibitor                                                                              0.01-5     0.01-1.5                                        Dispersant         0.01-10    0.1-5                                           Lube Oil Flow Improver                                                                           0.01-2     0.01-1.5                                        Detergents and Rust                                                                              0.01-6     0.01-3                                          Inhibitors                                                                    Pour Point Depressant                                                                            0.01-1.5   0.01-1.5                                        Anti-Foaming Agents                                                                             0.001-0.1  0.001-0.01                                       Antiwear Agents   0.001-5    0.001-1 .5                                       Seal Swellant      0.1-8      0.1-4                                           Friction Modifiers                                                                               0.01-3     0.01-1.5                                        Lubricating Base Oil                                                                            Balance    Balance                                          ______________________________________                                    

When other additives are employed, it may be desirable, although notnecessary, to prepare additive concentrates comprising concentratedsolutions or dispersions of the subject additives of this invention (inconcentrate amounts hereinabove described), together with one or more ofsaid other additives (said concentrate when constituting an additivemixture being referred to herein as an additive-package) whereby severaladditives can be added simultaneously to the base oil to form thelubricating oil composition. Dissolution of the additive concentrateinto the lubricating oil may be facilitated by solvents and by mixingaccompanied with mild heating, but this is not essential. Theconcentrate or additive-package will typically be formulated to containthe additives in proper amounts to provide the desired concentration inthe final formulation when the additive-package is combined with apredetermined amount of base lubricant. Thus, the subject additives ofthe present invention can be added to small amounts of base oil or othercompatible solvents along with other desirable additives to formadditive-packages containing active ingredients in collective amounts oftypically from about 2.5 to about 90%, and preferably from about 15 toabout 75%, and most preferably from about 25 to about 60% by weightadditives in the appropriate proportions with the remainder being baseoil.

The final formulations may employ typically about 10 wt. % of theadditive-package with the remainder being base oil.

All of said weight percents expressed herein (unless otherwiseindicated) are based on active ingredient (AI) content of the additive,and/or upon the total weight of any additive-package, or formulationwhich will be the sum of the AI weight of each additive plus the weightof total oil or diluent.

The invention is further illustrated by the following examples which arenot to be considered as limitative of its scope.

EXAMPLE 1 Preparation of Ethylene-1-Butene Copolymer

In a continuous polymerization, ethylene gas was continuously injectedinto a liquid stream composed of 40 weight percent 1-butene and 60weight percent isobutane at a rate sufficient to provide 8.5 weightpercent ethylene content, based upon the total weight of monomer. Thereactant stream containing ethylene, 1-butene, and isobutane wascontinuously fed into a 568-liter, stirred boiling reactor equipped witha water jacket for temperature control at a rate of about 370 kg perhr., wherein the vapor formed in the reactor is condensed in an overheadreflux condenser and returned to the reactor. A catalyst solution wasprepared by dissolution of solid 1,1-dimethylsilyl-bridgedbis(4,5,6,7-tetrahydroindenyl)zirconium dichloride into a 10 weightpercent solution of methylalumoxane in toluene, such that the Al:Zrmolar ratio in the solution was 500:1. The catalyst solution wascontinuously pumped into the boiling reactor at a rate sufficient toprovide a molar Zr concentration of 0.25×10⁻⁵. The temperature of thereactor was maintained at 160° F., and the reactor pressure wasmaintained at 170-175 psig (ca. 13 bar). The reactor contents werecontinuously stirred at a rate of 300 rpm. The reactor residence timewas 1 hour.

The product stream was continuously fed from the boiling reactor to aquench drum, where it was contacted with an aqueous solution of 350 ppmNH₄ OH. The unreacted monomer, solvent, and quench water were removedfrom the product by nitrogen stripping. The polymer product was thenfiltered to remove the catalyst residue.

The yield of ethylene-1-butene copolymer was about 70 kg per hour. Theethylene content of the copolymer was 22.8 weight percent, as determinedby proton NMR. According to an analysis by proton NMR, 69.6% of thepolymer chains in the polymer were found to have terminalethylvinylidene unsaturation, and 0% were found to have terminal vinylunsaturation. The polymer had a M_(n) of 4,666 and MWD of 2.3, asdetermined by gel permeation chromatography using a calibration curvefor a polydisperse EB copolymer with 20 wt. % ethylene content.

EXAMPLE 2 Preparation of Ethylene-1-Butene Copolymer

The polymerization was performed as in Example 1, except that thereactor temperature and pressure were 175° F. and 225 psig (ca. 16.5bar) respectively. In addition, the reactant stream consisted of aliquid stream composed of 38.5 weight percent 1-butene and 61.5 weightpercent isobutane into which ethylene gas was injected at a ratesufficient to provide 19 weight percent ethylene content, based upon thetotal weight of monomer. The reactant stream was fed into the reactor at20 a rate of 403 kg per hr.

The yield of ethylene-1-butene copolymer was 98 kg per hour. The polymerhad 38.9 weight percent ethylene content, 66.3% terminal ethylvinylideneunsaturation, and 0% terminal vinyl unsaturation. The M_(n) and MWD ofthe polymer were 4,325 and MWD of 2.34 respectively, as determined byGPC using the calibration curve for a polydisperse EB copolymer of 40wt. % ethylene content.

EXAMPLE 3 Preparation of Ethylene-1-Butene Copolymer

In a continuous polymerization, ethylene gas was continuously injectedinto a liquid stream composed of 55.7 weight percent 1-butene and 44.3weight percent n-butane at a rate sufficient to provide 12.9 weightpercent ethylene content, based upon the total weight of monomer. Thereactant stream containing ethylene, 1-butene, and n-butane wascontinuously fed at a temperature of about 75° C. into the bottom of astirred 1500 ml Monel autoclave reactor at a rate of about 1.92 kg perhour. A catalyst stock solution was prepared by dissolution of solid1,1-dimethylsilyl-bridged bis(4,5,6,7-tetrahydroindenyl)zirconiumdichloride in toluene, followed by addition of the dissolved catalyst toa 10 weight percent solution of methylalumoxane in toluene, such thatthe Al:Zr molar ratio in the stock solution was 1000:1. The stockcatalyst solution was continuously pumped into the reactor at a ratesufficient to provide a molar Zr concentration of 0.36×10⁻⁵. The reactorcontents were continuously stirred at a rate of 1500 rpm. Thetemperature and pressure of the reactor were respectively maintained at90° C. and about 260 psig (ca. 19 bar). The reactor residence time was30 min.

The product stream was continuously removed from the top of the reactor,quenched by contact with a 10 weight percent caustic solution, and thenscrubbed by contact with water to remove traces of the caustic. Both thequenching step and the scrubbing step also served to remove some of theash. Unreacted monomer, solvent, and water were then removed from theproduct polymer by flashing.

The yield of ethylene-1-butene copolymer was about 0.70 kg per hr. Asdetermined by proton NMR, the ethylene content was 16.9 weight percent,and 63% and 0% of the polymer chains in the polymer were respectivelyfound to have terminal ethylvinylidene and terminal vinyl unsaturation.The polymer had a M_(n) of 2,797 and MWD of 2.15, as determined by gelpermeation chromatography using a polydisperse EB copolymer with 20 wt.% ethylene as the calibration standard.

COMPARATIVE EXAMPLE 1 Preparation of Ethylene-1-Butene Copolymer

The polymerization was performed as in Example 1, except that thereactor temperature and pressure were 205° F. and 320 psig (ca. 23 bar)respectively. In addition, the reactant stream consisted of a liquidstream composed of 40 weight percent 1-butene and 60 weight percentisobutane into which ethylene gas was injected at a rate sufficient toprovide 27 weight percent ethylene content, based upon the total weightof monomer. The reactant stream was fed into the reactor at a rate of422 kg per hour.

The yield of ethylene-1-butene copolymer was 106 kg per hour. Thepolymer had a M_(n) of 8,027, MWD of 2.74, 55.1 weight percent ethylenecontent, 50.3% terminal ethylvinylidene unsaturation, and 4.3% terminalvinyl unsaturation.

COMPARATIVE EXAMPLE 2 Preparation of Ethylene-1-Butene Copolymer

In a continuous polymerization, separate streams of fresh ethylene gasand fresh 1-butene gas flowing at the respective rates of 4.3 and 8 kgper hr. were continuously mixed together, and the mixture compressed to1550 bar and chilled to 30° C. The chilled mixture of ethylene and1-butene gas was then fed to the top of a 3000 ml, jacketed, staged,steel autoclave reactor. A catalyst stock solution was prepared bydissolution of solid bis-(methylcylopentadienyl)zirconium dichlorideinto a 10 weight percent solution of methylalumoxane in toluene, suchthat the final Al:Zr molar ratio in the stock solution was 250:1. Thecatalyst stock solution was continuously pumped into the reactor at arate of 650 ml per hour. The reactor contents were continuously stirredwith an agitator operating at 1900 rpm. The temperature and pressure inthe reactor were respectively maintained at 125° C. and about 1330 bar.The reactor residence time was about 1 min.

The product stream exiting the bottom of the reactor was a mixture ofpolymer product, unreacted monomer, and catalyst fragments andby-products. After deactivation of the catalyst, unreacted monomer wasseparated from the polymer product in a high-pressure separator operatedat 195° C. and a reduced pressure of 63 bar, and the unreacted monomerwas recycled back to the reactor. The polymer product was thentransferred to a low pressure separator, operated at 1.1 bar and 180°C., for further separation and removal of residual unreacted monomer inthe product stream.

The yield of ethylene-1-butene copolymer was about 6 kg per hour. Asdetermined by proton NMR, the ethylene content was 55 weight percent,and 68% of the polymer chains in the polymer were found to have terminalethylvinylidene unsaturation. The polymer had a M_(n) of 2,000 and MWDof 3.6, as determined by gel permeation chromatography, using apolydisperse EB copolymer with 60 wt. % ethylene content as thecalibration standard.

POLYMER PROPERTIES

Properties of each of the EB copolymers prepared in Examples 1-3 andComparative Examples 1-2 were measured in accordance with the followingprocedures. As an additional comparison, certain of the properties werealso determined by these procedures for an isotactic poly(1-butene) withM_(n) of 1165 (hereinafter Comparative Example 3).

Scattering Factor S_(f) by Light Scattering

0.5 g of the EB copolymer was added to 9.5 g of S150NL mineral oil (5wt. % EB copolymer solution), mixed for approximately 16 hrs. at roomtemperature, heated and occasionally shaken in an oven at 80°-85° C. forseveral hours, and then filtered at 80°-85° C. About a 5 ml portion ofthe hot, filtered solution was then immediately quenched by placement inthe sample chamber of a Brookhaven light scattering goniometer whichcontains an index matching bath at a temperature of 20° C.

Light from a Spectra-Physics model 124B He-Ne laser (wavelength=632.8nm) was directed onto the sample, and the scattered light intensity at aforward scattering angle of 45° was recorded in units of photon countsper second using a Brookhaven B12000 correlator, where the intensitylevel was recorded every ten seconds for 60 minutes following thequench.

The results of these procedures for each of the Examples and ComparativeExamples are collected together in Table I following. In addition, FIG.3-A presents a plot of the scattered light intensity as a function ofthe time following the quench for the EB copolymer product prepared inExample 1. As shown in FIG. 3-A, average scattered intensity did notchange as a function of time after the quench for the duration of thetest. S_(f) was, therefore, zero. FIG. 3-B shows a plot of the scatteredlight intensity as a function of the time following the quench for thesolution prepared from Comparative Example 2. As shown in FIG. 3-B,I_(o) and I_(eq) were respectively 700 and 7000 counts per second,resulting in an S_(f) value greater than zero.

                  TABLE I                                                         ______________________________________                                                 I.sub.o (photon                                                                             I.sub.eq (photon                                       Example  counts/sec)   counts/sec)                                                                             S.sub.f                                      ______________________________________                                        1        300           300       0                                            2        300           300       0                                            3        700           700       0                                            Comp 1   300           480         0.6                                        Comp 2   700           7000      9                                            Comp 3   300           300       0                                            ______________________________________                                         *Comparative Example 3 is an isotactic poly(1butene) with M.sub.n of 1165

Ethylene Sequence Length (ESL) by C-13 NMR

1 g of the EB copolymer product was dissolved in 4 g of CDCl₃, whichalso contained 40 mg of chromium acetylacetonate as a paramagneticrelaxation agent. The solution so prepared was then used as a sample formeasuring the C-13 NMR spectrum. The C-13 NMR spectrum was recorded on aJEOL GSX400 NMR spectrometer at 100 MHz. The following instrumentconditions were employed: sample temperature, 30° C.; pulse flip angle,90°; pulse repetition delay, 3 seconds; number of acquisitions perspectrum, 8,000; and sweep width, 40,000 Hz. Proton decoupling wasemployed during acquisition, but not during recycle delay. Based upon ananalysis of the spectrum that included the contributions of the terminalgroups in the polymer chains, the triad concentrations X_(EEE),X_(BEE+EEB), and X_(BEB) were obtained, based upon which ESL wascalculated. The results of these procedures for each of Examples 1-3 andComparative Examples 1-2 are given in Table II following.

                  TABLE II                                                        ______________________________________                                        Example    X.sub.EEE                                                                            X.sub.BBE+EEB                                                                              X.sub.BEB                                                                          ESL                                       ______________________________________                                        1          0.051  0.138        0.148                                                                              1.55                                      2          0.164  0.268        0.123                                                                              2.16                                      3          0.052  0.144        0.160                                                                              1.54                                      Comp 1     0.342  0.300        0.070                                                                              3.24                                      Comp 2     0.298  0.312        0.091                                                                              2.84                                      ______________________________________                                    

Pour Point

A blend was prepared containing 2 weight percent of EB copolymerproduct, 0.2 weight percent of a dialkyl fumarate-vinyl acetatecopolymer lube oil flow improver sold commercially by Exxon ChemicalCompany, and a balance of S150NL mineral oil. The pour point of theblend was then measured according to ASTM Method No. D97. Table IIIpresents the results of the pour point measurements for each of Examples1-3 and Comparative Examples 1-3.

The pour points of twenty additional EB copolymer products, prepared inaccordance with the general methods described in the section entitled"Preparation of the Ethylene-1-Butene Copolymer," were measured via theprocedure described in the last paragraph. Table IV presents the pourpoint data for each of these copolymers, along with their ethylenecontents in weight percent and their number average molecular weights.The pour points for these polymers are reported in order of increasingethylene content as sample numbers 1-3, 5-9, 11-18, 20, and 22-24. TableIV also includes, for comparative purposes, the same data for the EBcopolymers of Examples 1 and 2, corresponding respectively to samplenos. 4 and 10, and Comparative Examples 1 and 2, correspondingrespectively to sample nos. 21 and 19.

FIG. 2 provides a graphical representation of the data in Table IV. FIG.2 plots pour point as a function of ethylene content, wherein the pourpoint of each copolymer in the plot is marked by a circle whose diameteris proportional to the M_(n) of the copolymer. The number associatedwith each circle is the sample number of the copolymer in Table IV.

Summary of Properties

Table III below summarizes some of the key property values determined asdescribed above for Examples 1-3 and Comparative Examples 1-3. The Tableincludes the ethylene content in weight percent, the number averagemolecular weight, the ESL value, S_(f) value, and pour point.

                  TABLE III                                                       ______________________________________                                        EB Polymer                                                                             Ethylene                      Pour                                   of       Content                       Point                                  Example  (wt. %)    M.sub.n                                                                              ESL    S.sub.f                                                                            (° C.)*                         ______________________________________                                        1        22.8       4666   1.55   0    -30                                    2        38.9       4325   2.16   0    -36                                    3        16.9       2797   1.54   0    -30                                    Comp 1   55.1       8027   3.24     0.6                                                                              -18                                    Comp 2   55         2000   2.84   9    -33                                    Comp 3   0          1165   --     0    -27                                    ______________________________________                                         *The respective pour points of S150NL mineral oil neat and a blend of         S150NL with 0.2 wt. % of LOFI were -18° C. and -30° C.,         determined by ASTM Method No. D97.                                       

As shown in Table III, Examples 1-3 all have S_(f) values of zero (i.e.,an absence of aggregation), satisfactory pour points of -30° C., and ESLvalues<2.50. This data describes EB copolymers which, under theconditions specified in the Examples supra, have insufficient ethyleniccrystallinity to act as sites for either copolymer aggregation in aquenched mineral oil solution or to adversely affect the pour point ofthe oil by participation in the crystalline wax network that forms asthe mineral oil is cooled. At the opposite extreme is ComparativeExample 1, which has S_(f) greater than zero, an unsatisfactory pourpoint of -18° C., and a relatively high ESL value of 3.24. This datadescribes an EB copolymer which has substantial ethylenic crystallinity,such that the copolymer both aggregates after solution quenching andadversely affects pour point by contributing to the formation of the waxcrystal network in the cooling oil. Occupying an intermediate positionis Comparative Example 2, which has S_(f) greater than zero, asatisfactory pour point of -33° C., and an intermediate ESL value of2.84. This data characterizes an EB copolymer with sufficient ethyleniccrystallinity to aggregate after quenching, but which is insufficient tocontribute to the wax crystalline network in a manner which adverselyaffects pour point.

The data in Table III further demonstrates that the isotacticpoly(1-butene) of Comparative Example 3 has a tendency not to aggregate,(i.e., S_(f) of zero) and has a relatively minor effect on pour point.This indicates that, relative to ethylenic crystallinity, isotacticcrystallinity due to relatively long 1-butene sequences in EB copolymerchains plays little or no role in copolymer aggregation or pour pointbehavior.

                  TABLE IV                                                        ______________________________________                                                               Ethylene Pour                                          Sample                 Content  Point                                         No.      Mn            (wt. %)  (° C.)                                 ______________________________________                                         1       1,627         15       -36                                            2       2,797         17, 13   -36                                            3       1,962         22       -33                                            4       4,666           22.8   -30                                            5       2,595         27       -33                                            6       1,932         28       -33                                            7       3,731         33       -33                                            8       2,742         35       -36                                            9       3,049         36       -33                                           10       4,325           38.9   -36                                           11       3,571         40       -36                                           12       6,655         41       -33                                           13       7,204         41, 35   -36                                           14       6,192         45       -36                                           15       3,370         50       -18                                           16       2,844         51, 46   -36                                           17       10,254        51       -18                                           18       4,353         53       -24                                           19       2,000         55       -33                                           20       11,869        55, 54   -18                                           21       8,027           55.1   -18                                           22       12,432        61       -18                                           23       3,152         61       -18                                           24       3,062         62, 64   -21                                           ______________________________________                                    

EXAMPLES 4-6

Preparation of Succinic Anhydride Functionalized EB Copolymer (EBSA)

In separate runs, each of the EB copolymers prepared in Examples 1-3 andpulverized maleic anhydride is charged at a ratio of 1.6 moles of maleicanhydride to one mole of EB copolymer under dry nitrogen and atatmospheric pressure to a 100 ml pressure reactor equipped with astirrer and a thermocouple and heated by means of an electric heatingmantle. The reaction mixture is heated to 70° C., after which thereactor is gently purged by bubbling dry nitrogen through the liquidreaction mixture for 15 min. The purging is then terminated and thereactor sealed. The reactor temperature is then raised to a temperatureof 220° C. and is maintained at that temperature for 6 hrs. whilestirring. The reaction is then terminated by cooling the reactionmixture to about 60° C., after which the liquid mixture is transferredto a glass beaker. Unreacted maleic anhydride is stripped off by passingdry nitrogen gas through the liquid at 140° C. The liquid product soprepared in each run is expected to contain EBSA and unreacted EBcopolymer and to have little or no observable sediment. The product isalso expected to have an AI value of at least about 65 to 75, a value ofF between about 1.10 and 1.25.

EXAMPLES 5-7 Preparation of EBSA-Polyamine Dispersants

In separate runs, dispersant materials are prepared utlizing liquid EBSAproducts as prepared in Examples 4-6. The succinic acid anhydridesubstituted polymers are dissolved in an equal amount by weight ofS150NL mineral oil. To the polymer solution is added tetraethylenepentamine (TEPA), and the mixture is heated to 140° C. under nitrogenwhile stirring for about 2 to 4 hours. The molar ratio of total polymerto polyamine in terms of succinic acid equivalents to TEPA charged is 2to 1.

EXAMPLE 8 Preparation of a Mannich Base Dispersant Additive

Alkylation of the Phenol

About 50 grams of the EB copolymer prepared in Example 1 is dissolved in100 ml of chlorobenzene and added to a solution containing about 10 gramof phenol in 300 ml of chlorobenzene. While stirring at room temperatureunder nitrogen, 0.5 g of BF₃ gas is bubbled into the charged solution,and the reaction mixture is stirred while the temperature is increasedto 50° C. for about one hr. The reaction mixture is then neutralizedwith gaseous ammonia until a neutral pH is obtained. The solution isfiltered and the filtrate is heated to 150° C. to distill off thesolvent and excess phenol. About 90% or more of the EB copolymer isexpected to alkylate with the phenol to form EB copolymer substitutedphenol.

Mannich Base Condensation

To a 500 ml round-bottomed reaction flask is charged 25 grams of S150NLlubricating oil in which is dissolved 25 grams of EB substituted phenolas just prepared. 0.61 g of 1,6-hexanediamine and 0.35 g of formaldehydeare then added to the flask at 30° C. under nitrogen. The mixture isheated to 115° C. and kept at that temperature for 1 hour, after whichthe temperature of the reaction mixture is raised to 130° C. andmaintained at that temperature for 45 min., all the while sweeping thereaction flask with dry nitrogen gas. The stripped reaction mixture isthen cooled to room temperature, diluted with 100 ml of heptane, andfiltered. The filtrate is then stripped at 130° C. with dry nitrogen gasto remove heptane.

EXAMPLE 9 Oxidized EB Copolymer

A 1500-ml glass reactor equipped with gas inlet and outlet tubes, athermometer, and a stirrer is charged with 800 grams of EB copolymer asprepared in Example 3. The temperature is raised to 200° C. whilestirring the copolymer. Dry air is bubbled through the copolymer via theinlet tube for 6 hrs., all the while maintaining the temperature at 200°C. At the end of 6 hours, the air flow is terminated, and nitrogen isbubbled through the copolymer while cooling the reactor to roomtemperature.

EXAMPLE 10 Preparation of a Nitrogen-Containing Dispersant from OxidizedEB Copolymer

A nitrogen-containing dispersant material is prepared utlizing oxidizedEB copolymer product as prepared in Example 9. The oxidized EB copolymeris dissolved in an equal amount by weight of S150NL mineral oil. To thepolymer solution is added tetraethylene pentamine (TEPA), and themixture is heated to 140° C. under nitrogen while stirring for about 2to 4 hours. The molar ratio of total polymer to polyamine in terms ofequivalents of carboxyl groups in the oxidized EB copolymer to TEPAcharged is 2 to 1.

What is claimed is:
 1. Lubricating oil dispersant additive comprisingthe reaction product of:(a) at least one alkyl-substitutedhydroxyaromatic compound formed by the alkylation of at least onehydroxy aromatic compound with an ethylene-1-butene copolymer, whereinthe copolymer before alkylation comprises from 1 to about 50 weightpercent ethylene derived units and from about 99 to about 50 weightpercent 1-butene derived units, based on total copolymer weight beforealkylation, and has a number average molecular weight between about1,500 and 7,500, ethylvinylidene groups terminating at least about 30percent of all copolymer chains, and an S_(f) value of about zero; (b)at least one aldehyde reactant; and (c) at least one nucleophilicreactant.
 2. Lubricating oil dispersant additive comprising the reactionproduct of:(a) ethylene-1-butene copolymer comprising from 1 to about 50weight percent ethylene derived units and from about 99 to about 50weight percent 1-butene derived units, based on total copolymer weight,and having a number average molecular weight between about 1,500 and7,500, ethylvinylidene groups terminating at least about 30 percent ofall copolymer chains, and an S_(f) value of about zero; and (b) anoxygen-containing gas.
 3. Lubricating oil dispersant additive comprisingthe reaction product of:(a) an oxidized ethylene-1-butene copolymerformed by contacting(i) ethylene-1-butene copolymer which comprisesbefore oxidation from 1 to about 50 weight percent ethylene derivedunits and from about 99 to about 50 weight percent 1-butene derivedunits, based on total copolymer weight before oxidation, and has anumber average molecular weight between about 1,500 and 7,500,ethylvinylidene groups terminating at least about 30 percent of allcopolymer chains, and an S_(f) value of about zero; (ii) anoxygen-containing gas; and (b) at least one nucleophlic reactant.